Final New Build BOTD

Transcription

Non Domestic Buildings New Build
Technical Toolkit
Practical Aspects
Non Domestic Building
2.2.1
New Build
Practical Aspects
NZEB Practical Aspects (NBND)
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Maximise passive design strategies
Maximise energy efficiency
o Reduce energy base load
Primary energy to be within the Reference Building range (kWh/m2/yr)
o Retail AC 200-260
o Hotel AC 243-285
o Office NV 35-70
o Office AC 100-135
o Primary School 40-50
Consider location of renewable sources
o On site RE
o Off site RE
o Off grid
Buildings account for 40% of total energy consumption and 36% of CO2 emissions in Europe, according to the Building
Performance Institute Europe report Nearly Zero Energy Buildings - Paving the way for effective implementation of
. In order to meet ambitions EU targets to reduce greenhouse gas emissions by 80% from 1990
levels by the year 2050, the building stock across Europe must be looked at in terms of potential for energy reduction.
New builds should be built to Near Zero Energy Building (NZEB) standards in order to help meet these targets.
The sole responsibility for the content of this toolkit lies with the authors. It does not
necessarily reflect the opinion of the European Union. Neither the EACI nor the
European Commission are responsible for any use that may be made of the
information contained therein.
The three main principles behind NZEB are:
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Energy Demand reduce as much as is practicable the amount of energy required in a building in terms of
heating/cooling, ventilation, lighting etc.
Renewable Energy Share produce thermal and electrical energy required for the building by locally sourced,
renewable means
Primary Energy & CO2 Emissions primary energy related to the total energy delivered to the building, and
equivalent CO2 emissions
This section outlines the practical aspects required for the successful design and build of a new NZEB domestic property.
In particular, key areas are:
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F
NZEB Design Approach
Site Management
Quality Control
Building Orientation
User Behaviour
NZEB
Financial Too
Further Information:
Ecofys Renewable Energy For Everyone
Building Performance Institute Europe - Principles For Nearly Zero Energy Buildings
European Union Law - Energy Performance Of Buildings Directive
Technical Toolkit
Non Domestic Buildings
2.2.1.1
New Build
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o Retail AC 200-260
o Hotel AC 243-285
o Office NV 35-70
o Office AC 100-135
o On site RE
o Off site RE
o Off grid
The concept of near or net zero energy buildings (NZEB) is relatively new and as yet no precise definition exists in the
UK, but broadly can be taken to mean - a building which itself produces the same amount of energy per annum, as it
uses over the same period. The energy can be produced on-site or off-site, and the building can be connected to the
grid or stand-alone off-grid.
The EPBD Energy Performance of Building Directive (Recast) became effective from 9th July 2010, and states that:
st
D
(Article 9a)
and
31 December 2018, new buildings occupied and owned by public authorities are nearly zero(Article 9b)
The Buildings Performance Institute of Europe has written a report on how to implement NZEB across Europe, based on
current status and principles of low energy buildings: Principles for Nearly Zero Energy Buildings (2011).
Definitions Of NZEB
There are currently three possible definitions of nZEB:
1) Defined at a European level through the Energy Performance of Buildings Directive;
2) Defined at National level
a. Through legislation or regulation;
b. Through projects and/or benchmarking criteria;
3) Key Defining Characteristics of an nZEB Building;
1) European level through the EPBD Definition
The EPBD, Article 2.2 loosely defines an NZEB, which is open to each European country to interpret, in line with its own
building regulations and standards. As the EPBD does not give any details of energy performance calculation framework,
it is left to the Member States to define them, taking into account local conditions.
zeroenergy performance, as determined in accordance with Annex I. The
nearly zero or very low amount of energy required should be covered
to a very significant extent by energy from renewable sources,
including energy from renewable sources produced on-site or nearby;
The Federation of European Heating, Ventilation & Air Conditioning (REHVA) set up a task force in 2010 to help define
and outline the NZEB philosophy:
 The Path Towards 2020 Nearly Zero Energy Buildings
 How to Define Nearly net Zero Energy Buildings
2) National Definition Non Domestic Building: New Build
There is currently no legislative or regulatory definition of nZEB in the United Kingdom, but for the purpose of the
SustainCo project, an nZEB new build non domestic building can be defined using key energy performance criteria as
follows:
An nZEB building other than a dwelling in the UK, will have a Primary Energy need for the operation of the
building, of between 35 kWh/m2/yr to 285 kWh/m2/yr depending on the type of Reference Building. This shall be
achieved by controlling heat loss and maximising heat gains through the building fabric; designing efficient
systems and controls for heating, hot water, cooling, refrigeration and lighting services.
It is acknowledged by the partners on the SustainCo project, these targets are extremely challenging, but are achievable
by using the details and principles outlined elsewhere in this Technical Toolkit.
The following table sets out the benchmark criteria used to develop the above definition of new build nZEB dwellings.
Description Units
Primary
Energy
(Referance
Buildings)
2013 Building Regulations- Wales
Minimum requirements/ Limiting
fabric parameters for individual
elements
Minimum requirements for new
thermal elements
M3(hr.m2)
U value:
External
Wall
W/m2/k
2
W/m /k
nZEB Standard
Retail AC - 200260, Hotel AC 243-285, Office
NV - 35-70,
Office AC - 100135, Primary
School - 40-50.
kWh/m2/yr
Air
Tightness
U value:
Roof
2013 Building Regulations- England
10.0 at 50 Pa
10.0 at 50 Pa
0.35
0.35
0.12
0.25
0.11 insulation
at ceiling level
and rafter level
0.25
or 0.15 for flat
roofs
U value:
Floor
W/m2/k
0.25
0.25
0.13
U value:
Windows
U value:
Pedestrian
Doors
U value:
High
Useage
Entrance
Doors For
People
W/m2/k
2.2
2.2
1.5
W/m2/k
2.2
2.2
1.5
W/m2/k
3.5
3.5
3) Key Defining Characteristics of an nZEB Building
Aside from where individual countries have specifically defined what constitutes an nZEB building,
Torcellini et al (2006) provides a set of broad general principles, outlining key defining characteristics
of 4 approaches to nZEB:
Net Zero Site Energy the building/site produces at least an equivalent amount of energy, as that used per annum
when accounted for at the building/site.
Net Zero Source Energy the building/site produces an equivalent amount of energy, as that used per annum when
accounted for at the source. Source energy refers to the primary energy used to generate and deliver energy to the
T
source energy, imported and exported energy is multiplied by the
appropriate site-to-source conversion multipliers.
Net Zero Energy Costs the amount of money an energy supplying utility pays to the building/site owner for energy
exported to the grid, and is at least equivalent to the amount the building/site owner pays to the energy supplying
utility for energy, services, connections fees
Net Zero Energy Emissions the building/site produces at least the same amount of emissions free renewable energy as
it uses from emission producing energy sources per annum.
Some also consider the following types of development as NZEB:
Net Off-site Zero Energy Use where a building is considered to be NZEB, if all of its energy use, is derived from
renewable sources that are located off-site.
Off the Grid where a building is not connected to any power/utility supply, and so must be able to produce and store
its own energy. They are also known as energy autarkic buildings.
Note: NONE OF THE ABOVE consider embodied energy or embodied carbon in their definitions or calculations.
How Is NZEB Achieved?
Regardless of definition, the primary consideration when designing an NZEB is to initially reduce the energy demand of
the proposed building using energy efficient appliances, lighting, smart heating/hot water/lighting controls etc., THEN
consider the most effective method to deliver energy to the building/site, including demand side renewables. Ways in
which to reduce energy use, and then ways to produce energy by renewable sources, are discussed throughout these
toolkits.
F
N
)
E
Diagram (Source: Swegon Air Academy)
Cost Optimal
The EPBD (Recast) also discusses that a NZEB must be cost-optimal See Article 2.14 for a full definition. Cost-optimal
refers to the range of energy performance levels where the cost-benefit analysis for the estimated economic life-cycle is
positive having due regard to energy-related investment costs, maintenance and operating costs and disposal costs.
Fig2 C
SE‘VE C
Issues To Be Considered
When architects and clients are considering an NZEB project, the following 6 areas should be actively considered in the
design process:
1) Design and objective - decide on which NZEB definition the project will be based around. For example,
equivalent energy, equivalent money or equivalent emissions and base the design around the appropriate
criteria;
2) Consider the local/regional climate and weather conditions and seasonal patterns - NZEB designs are
particularly sensitive to such variables, and what makes sense in a northern European or Scandinavian country,
wont in a Mediterranean country. This will also impact on the project design and objective;
3) Passive strategies these will vary from location to location and be influenced by local weather and climate.
Projects in colder northern climates might focus on insulation and heat recovery, whilst projects in warmer
more southern European climates may tend to focus on shading and natural ventilation;
4) Energy efficiency
this will commence with the minimum performance standards required by
local/regional/national legislation or regulations, and cover everything from insulation, airtightness, ventilation,
air quality, conservation of energy etc.
5) Renewable Energy Systems (RES) consideration must be given to integrating RES into the NZEB design from
the first concept sketches, for example building orientation will help maximise sunlight for PV systems and solar
hot water;
6) Technology by their very nature NZEB projects will require technology to maximise the benefits of any given
specification.
Barriers For NZEB
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Integration of renewable technologies into small scale developments
Perception of renewable technology as costly and unreliable
Reluctance for main stream developers/builders to move away from traditional forms of design and
construction
Challenges to improve construction skills to build new airtight and energy efficient designs
Lack of significant numbers of clients willing to try new designs and technologies
Perceived and actual higher capital cost of building an NZEB
Building Performance Institute Of Europe - Principles Of Nearly Zero Energy Energy Performance Of Buildings Directive
Buildings
Whole Building Design Guide - Information On NZEBs
The Federation Of European Heating, Ventilation & Air Conditioning (REHVA) - The Path Towards 2020 Near Zero
Energy Buildings
The Federation Of European Heating, Ventilation & Air Conditioning (REHVA) - How To Define Nearly Net Zero Energy
Buildings
International Passive House Association - Guidelines For Passive House Design
National Renewable Energy Laboratory Torcellini, P., Pless,S., & Deru, M. (2006) - Zero Energy Buildings: A Critical Look
At The Definition
Whole Building Design Guide - Net Zero Energy Buildings
Video Links:
American Society Of Heating, Refrigerating And Air-Conditioning Engineers (ASHRAE) - Achieving Near Zero Energy
Buildings
Leonardo Energy - Webinar Near Zero Energy Buildings
Technical Toolkit
Site Management
2.2.1.2
New Build
Site Management
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o Retail AC 200-260
o Hotel AC 243-285
o Office NV 35-70
o Office AC 100-135
o On site RE
o Off site RE
o Off grid
Site management is the process of overseeing the daily functions of a new-build or retro-fit project, to ensure the
project is completed on time, within budget and to the correct standard and quality as specified.
Depending on the scale of the project, a site manager may be responsible for the entire site or project, however on
larger projects, the site manager may be responsible for a portion of the project and along with other site managers,
report to a senior manager who is coordinating the entire project.
Why Is Site Management Required?
A site manager or someone who fulfils this function is required on all construction related projects regardless of size or
scale, whether new-build or retro-fit. The site manager is there to take responsibility and coordinate the construction
work necessary to actualise the project.
Whilst a building project is taking place, the site manager is to monitor progress of the work, deal with technical or
trade issues as they arise, organise the delivery of materials, and schedule the order of trades to attend on-site.
The site manager is also the liaison point with other members of the professional design team such as architects and
T
C
Perhaps most importantly of all, the site manager is to ensure the project complies with the relevant construction
related legislation such as:
i)
Planning - the project is constructed in the agreed location and to the approved dimensions or the retrofitting work complies with local conditions
ii)
Building Regulations - the completed structure (either new-build or retro-fit) conforms to or exceeds the
appropriate building standards this is particularly true for NZEB projects, where the design might require
construction details and installation of plant/equipment beyond those normally required
In effect, the function of a site manager is to control performance of the project, identify any issues or potential issues,
develop solutions to address or eliminate these issues, recognise and correct any sub-standard workmanship and
materials.
Building Economics
With a non-domestic project building, control of the project has even greater financial implications for both the main
contractor and the client. The success of otherwise of a commercial building project is dependent on the prevailing or
projected market conditions and the location of the building, which will have an impact on the potential sale or rental
market. Delays in project completion will reduce potential sales or rental income.
Often, commercial projects are on relatively small parcels of land, and the only way for the client to make a return on
their investment, is for the buildings to be designed as multi-storey buildings. This presents a number of challenges for
the site manager, for example.
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Below ground car-parking: its vital to ensure works to the basement and podium levels are carried out in
accordance with the design, with any anomalies brought to the attention of the design team immediately. Loss
of car-parking spaces will have a negative effect on the ability to rent or sell commercial space in the building
above;
Services: all services should be designed on an integrated basis that can be accommodated within the available
service ducts, hollow floor/ceiling voids, and around the building frame. Since commercial space is let or sold by
the m2, it is vital that rentable/saleable floor space is not lost to poorly designed service ducts/voids or where
such spaces that have to be increased in size. As Building Information Modelling (BIM) becomes more
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widespread in the industry, service design and integration, especially with the work of the structural engineer,
should make this less on an issue;
Fire safety: as with all building projects, fire safety is of supreme importance, but perhaps more so, on a
commercial build. Compliance with the Fire Office, national or local regulations will often be the requirement to
receiving a certificate of compliance. Failure to obtain such a certificate will have two impacts on the economics
of the projects i) the cost of rectifying the works to satisfy the requirements of the certificate ii) the loss of
rental or sale income whilst the remedial works are being carried out;
Sound transmission: regardless of whether the building is used by one or multiple occupants, it is important to
block the transmission of sound between individual office suites, be they adjoining on the same floor, or on the
floor directly above/below. It will be the job of the site manager to ensure the design to prevent such
transmission is strictly adhered to. Rectification of complaints from future tenants about noisy neighbours will
prove expensive, whilst any buyer of the building may well take civil action in the courts to cover the cost of
such work.
How Is Site Management Achieved?
A site manager is required to have full control over their project, which can be achieved by making informed decisions in
a timely advanced manner thus keeping the project timeline on its critical path, the work within budget and to the
correct quality. Such planning eliminates the need to make
, that are often disruptive to the flow of
work, lead to cost over-runs and potentially poor quality work.
In order for a site manager to fully control their project, they should have suitable knowledge, training and experience in
a number of areas, some of which are listed below:
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Sustainable construction technology
Site surveying and setting out
Estimating and measuring
Contractual and legal responsibilities
Managing sub-contractors
Project planning
Project control and monitoring
Building services
Managing quality on site
Managing health and safety on site
Selection of the site manager it is vital the person selected for a project has the necessary experience, training and
knowledge appropriate for the task at hand. This is especially true for low energy projects, for example:
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Do they understand basic building physics and the impact caused by the movement of moisture through
building fabric?
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Do they understand the requirements for airtightness and have the ability to critically inspect and assess such
work, or the impact on airtightness caused by the penetration of the building fabric?
Do they understand the importance of a Door Blower Test and the negative consequences on the projects
Critical Path, if such a test is failed?
Do they understand that work on low energy projects should be carried out in a collaborative manner i.e.
rather than in a succession of individual trades working in isolation i.e.
?
Are they familiar with low-energy technology, and understand how to coordinate and inspect its installation?
The failure to select the most suitable site manager for a low energy construction project could have profound
consequences for their ability to deliver the project on time, within budget and to the correct standard.
Project Timeline & Critical Path
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Identification of the tasks necessary to complete a project is vital in order to develop
C
P
Confirm the project start and completion dates
Identify all tasks required for the project and in the correct sequence
Calculate time required on site by the various trades
Identify the need for in-house trades or the requirement to sub-contract
B
Schedule delivery of materials and resources to site, to suit trades
Calculate lead-in time(s) for specialist materials or those elements that require off-site manufacture
With all the key information now identified, isolate any periods or gaps where work may be delayed, and
readjust dates/times to ensure a continuous timeline and Critical Path
Identify the Critical Path and key milestones
Confirm all trades are available for when scheduled
Confirm and book deliveries
Confirm and book materials and elements with lead-in times
Cost Analysis This is a vital economic breakdown of a project when it is actually up and running to help the contractor
look at cash-flow and assess the day-to-day value of the project. Cost analysis is not the same as a Bill of Quantities
rather it looks at the cash flow of a project which can help a contractor to improve their performance overtime. Some of
the factors that cost analysis considers are:
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Projected weekly/monthly costs over the life of a project
Actual expenditure against these projections
Differences between budgeted and actual costs
Outside factors that may increase costs e.g. fuel
Subcontractor estimated/quoted costs versus actual costs
Costs associated with delays due to poor timeline development or unforeseen events e.g. weather
Variations/change orders especially if they lead to delays or contract extension
Variations/Change Orders this is where a request to add or omit work, to that originally specified is requested. The
request can come from the Client, the project design team (architect or engineer), the main contractor, sub-contractor
or material/element supplier. There are two main consequences to such requests:
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Adjustment to the project timeline and Critical Path extend or reduce the completion date
Financial who pays for
o additional work
o contract extension
Before such a request can be approved, it is vital that all parties involved understand the following:
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What exactly is being requested e.g. change in design, substitution of a specified material?
What is the scope of such a change e.g. significant or minor?
Who will be responsible for effecting the requested change e.g. main contractor, sub-contractor, supplier?
What is the financial cost of such a request e.g. budget reducing or budget increasing?
What is the timeline cost of such a request e.g. longer or shorter completion date?
Who is responsible for paying for such a request?
Who is responsible for approving such a request?
Quality Control A key component of all low energy building contracts. The site manager is ultimately responsible for
checking all work, and upon discovering sub-standard work, shall have the authority and knowledge to insist upon
suitable rectification at the sole expense of the responsible trade(s).
Site Waste Management Plans Such plans are often a legal requirement or considered good practice within the
construction industry. They can help a contractor improve their costings and profitability on a project, especially a retrofit project, where materials fit for recycling or reuse can be identified for salvage and set aside for reuse and resale to a
responsible 3rd party.
Beyond Completion
Often, the post-completion performance of non-domestic buildings does not live up to either the clients or the
occupiers expectations. It has been suggested that post occupancy monitoring should be carried out as part of the
project management function, for perhaps up to 12 months after the building initially starts being used to look at why
nt can learn from any mistakes identified, for
example:
i)
ii)
iii)
Poor predictive techniques of future building energy usage: This could be because the design team only
considered office space and not circulation or other common areas, or only looked at heating/cooling,
lighting, ventilation, but not at passenger lifts,
Changes to the building design during construction: The insulation, ventilation and thermal design of the
building may have been amended to save costs, the building service controls (BMS) could have been
simplified;
The building may not have been constructed as designed (including variations). Air-tightness may not be as
effective as designed, insulation may not have been fully installed in all areas of the wall and roof, the
external glazing may not be performing as intended;
iv)
The building occupiers may not be using the building as intended. They may change the internal layout and
therefore affect ventilation and heating, they may not understand how to use the service controls to ensure
maximum efficiency, the building owners may not have a correctly scheduled maintenance plan in place for
plant and equipment;
Construction Industry Federation
Chartered Institute of Buildings
Technical Toolkit
Quality Control
2.2.1.3
New Build
Quality Control
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o Retail AC 200-260
o Hotel AC 243-285
o Office NV 35-70
o Office AC 100-135
o On site RE
o Off site RE
o Off grid
The definition of
depends on the perspective of the person evaluating the finished product. In the case of the
construction industry this means the perspective of either the Client or the contractor.
Any misunderstanding between the two parties tends to be magnified by the wording in the contract documents that
usually provides a vague definition of quality under the guise of phrases such as
or other such non-descript terms. This allows plenty of scope between the Client and the contractor in the
areas of understanding and practice for example:
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Understanding - what the Client understood their finished building to deliver and what the contractor
understood they actually had to deliver
Delivery - what the Client was expecting to be done, and what the contractor actually did
Delivering and Measuring Quality
Quality is not a stand alone descriptor of the success or otherwise of a building project. The UK Construction Industry
Council (CIC) developed a Design Quality Indicator (DQI) to assess the quality of buildings and identified three main
areas:
1) Functionality the arrangement and inter-relationship of space and the way the building is used;
2) Impact the buildings ability to create a sense of space and create a positive effect with the local community
and environment;
3) Quality a measure of the engineering performance of the building, its integrity, the robustness of its finishes,
fittings and systems
Fig1. Building Quality Attributes (Source: Construction Industry Council CIC)
The Clients Perspective
On commercial projects, the client will want a completed building that is attractive to potential renters and buyers, but
will not necessarily want to pay any premium associated with such an outcome.
This conflict of outcome vs cost is reflected in low-energy buildings, where there is an approximate 10% cost premium.
This additional cost may well be compounded by the lack of available skilled construction personnel who can be used on
site, to deliver the project on time and within the enhanced budget.
The client on such a project may also be at a disadvantage, as they may neither be familiar with the construction
industry, and/or with the type of commercial building they are commissioning.
Whilst the client may not have an intimate knowledge of construction, they will have a firm grasp of finance and will
generally understand that waste, whether time and/or materials, will lead to an increase in costs and potentially a
reduction in quality as work is brought back on schedule.
Issues to be Considered
In order try and eliminate the intangible and personal perspective of quality and to deliver quality control on site, three
factors need to be considered:
Time adequate quality control can only be achieved if sufficient time is given to both producing and evaluating a
finished building. Adequate construction time is delivered through a suitable timeline and Critical Path, whilst quality
evaluation is a
construction activity. It can be seen therefore the perception of quality is the anticipation of the
fruition of a future event i.e. the completion of a building, but it is only through subsequent evaluation of that event i.e.
Location quality control is very much a function of the location of where any construction is taking place and may take
many forms such as:
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Local market conditions
Local client expectations
Type of demographic a particular building is aimed at
Scale and activity of the local construction sector
Restrictive or open planning process
Ease of access to local development funding and client mortgages
These will differ from country to country, will be different within regions of the same country and may indeed vary
within different areas of the same city.
Specification the overall finished product should be of a high quality. This will be achieved if all the components or
elements of the building are tightly specified for the functioned they are required to do, and will take account of the
factor of Location e.g. the level of quality that is acceptable in one building, might not be acceptable in another
situation.
Why Is Quality Control Required?
In order to construct low energy buildings, quality control of the building process has taken on a higher significance than
traditionally given in the construction sector. Until recently, poor quality workmanship was identified and rectified
during the
process, but this tended to be limited to issues that mainly concerned the structural integrity or
aesthetics of a building.
With low energy buildings, more attention to detail during the initial construction phase is required, for example air
tightness and thermal continuity. It is important that insulation is properly joined and that openings (windows, external
doors) are correctly sealed to prevent air leakage. Traditionally, such details have being hidden and therefore ignored,
but are critical for the construction of low energy buildings
Such attention to detail will produce buildings that have an enhanced internal environment, higher levels of occupant
satisfaction and higher comfort levels. In commercial buildings this translates into improved productivity.
In practice, what little post-construction evaluation takes place has shown the energy performance of a completed
building is often worse than that of the design performance, so in order to increase the potential for actual
performance, quality control during the construction process is vital. This can best be achieved by considering the
following:
Brief clear and appropriate for the proposed development
Simplicity the building must function and operate in a simple manner, but not at the exclusion of innovation
Design & specification must be completed and agreed before work on site commences
Modelling design performance based on the final agreed design and specification, to be used as a benchmark for postconstruction evaluation
Detailing close attention must be paid to construction especially to important details associated with air tightness,
insulation and around openings
System thinking everyone works together in their respective areas e.g. the design team and the trades on site, but also
their needs to be teamwork and communication between the design team and the trades themselves
How Is Quality Control Achieved?
A leading UK based Building Scientist Bill Bordass suggests the following are key objectives towards achieving high levels
of quality control on a low energy build:
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Getting it right: Robust buildings
Get the brief right, based on practical insight
Get the standards right: avoid mission creep
Get the fabric right: passive measures
Get the services right: gentle engineering
Get the other things right: ICT, catering etc.
Get the controls right; and their user interfaces
Get it built right; with a suitable procurement path
Get it finished right: commissioning, operator and user engagement, handover, aftercare
Get it operated and used right, information, training, monitoring and review, troubleshooting and fine tuning
Keep it up to the mark, monitoring, feedback and continuous improvement
D
r
Sometimes, a commercial project runs into difficulty, because of a lack of integrity, the relationship between the client
and contractor breaks down, and they end up in dispute. This distraction takes time, effort and resources away from
addressing the issues raised.
All commercial projects will be managed through a nationally recognised form of contract, which will contain a
mechanism for dis
I
with issues as they arise.
Commercial quality control - is a potential way to deal with quality issues as they arise. The process was developed in
the America nuclear power industry, where issues of quality are crucial. A simplified version could be used on big
commercial construction projects, so issues are dealt with as they arise, instead of after completion- when lengthy legal
proceedings will delay and make any remedy more expensive.
An independent oversight of the project takes place as they occur during the build phase, looking at construction,
project management, budget, schedule, document control and key events. The oversight provides a verification and
non-adversarial assessment of progress on the project.
This independent oversight eliminates an over optimistic views of either the client regarding the budget or the
contractor regarding the schedule and completion dates. It also helps to keep track of all over-runs, be they cost or
delays whilst they may be individually small, such numerous changes will have an accumulative adverse effect, that
the contractor and client should be made aware of.
Disputes between client and contractor can be dealt with immediately using contemporaneous documents, rather than
trying to recall events some years later in a legal setting. This is clearly more advantageous as any remedy is immediate
and means the project is completed as intended.
Build With Care - Delivering A Low Energy Building- Making Quality Commonplace
Construction Task Force - Rethinking Construction 1998 The Report Of The Construction Task Force To The Deputy
Prime Minister On The Scope For Improving The Quality And Efficiency Of UK Construction (The Egan Report)
Build Up - Refurbishing Europe: An EU Strategy For Energy Efficiency And Climate Action Led By Building Refurbishment
International Risk Management Institute - Getting A Grip On Quality In The Constructed Project: Defining Quality
Useable Buildings
Technical Toolkit
2.2.1.4
New Build




o Retail AC 200-260
o Hotel AC 243-285
o Office NV 35-70
o Office AC 100-135
o On site RE
o Off site RE
o Off grid
Building Orientation is concerned with the location and positioning of a building on its site, in order to maximise passive
solar gains.
However, it is not always possible to position a building in its optimum location on site due to a number of factors:




Local planning conditions building line
Is the site is rural or urban issues with neighbours
Is the site a green or brown field financial resources required to clean a site before the build even commences
Archaeological or ecological features on site may limit development potential of site
1 is worst for daylighting - 3 is good - 2 is best
Fig1. Building Orientation (Source: Autodesk).
Why Is Building Orientation Important?
In commercial buildings, the optimum orientation of a building will have a positive influence on the running costs of the
building, levels of commercial activity and the wellbeing of the occupants, where the use of windows maximises natural
daylight:


Improved lighting quality daylight can penetrate further into a building, providing a natural light spectrum best
suited to human vision, thus enhancing the working environment;
Better health and comfort for building occupiers people are naturally attuned to the gradual variation in
intensity and spectrum of natural daylight, which invokes a improve mood and reduces discomfort and stress.
Such a variation is not possible with current artificial lights and controls;
Over the winter months, maximising natural daylight can help i) offset the mood swings associated with
symptoms of Seasonal A
D
SAD
used to regulate sleep and body temperature;
Occupiers tend to experience a sense of wellbeing when being able to see outside. This is enhanced when the
o
o
o

Skyline
U
H
Increased productivity the most significant cost to any business is staff cost. Over time, staff costs will exceed
the capital cost of the building. Employees exposed to high levels of natural daylight have been shown to be
more productive, take less sick time and are more creative
How Is Building Orientation Achieved?
The most efficient method to optimise a building location on a site is to plot the solar-path over the site. This is carried
out using a variety of tools such as GPS, sun-charts and computer software which can plot the solar-path over the site.
These methods make allowances for the constantly shifting nature of the solar-path. CAD and Google Sketchup can
create a site specific simulation, allowing designers to amend plans accordingly.
Two key pieces of information required to plot a solar-path are:
1. Altitude of site the angle above the horizon
2. Azimuth of the site the angle measured around the horizon, usually measured from the north increasing
towards the east essentially the direction from which the sun comes
Both of these are site specific and will help establish the amount of solar energy reaching the site, which will influence
both building and renewable system design.
Fig3. D
T
S
P
A
A Site (Source: Royal Institute of British Architects)
Orientation is measured by the azimuth angle of a surface relative to true north. Successful orientation rotates the
building to minimize energy loads and maximize free energy from the sun and wind. - See more at:
http://sustainabilityworkshop.autodesk.com/buildings/building-orientation#sthash.NdjhcbLb.dpuf
Fig4. Azimuth Angle (Source: Autodesk)
Commercial buildings have slightly different considerations to dwellings as they are places of work, so as well as an
occupier wanting to reduce their running costs they also owe a duty of care to their employees:
Maximise southern exposure the south elevation provides the most daylight access and control of solar gain. Space on
this elevation should be suitable for variation in sunlight. Occupiers do need to be mindful of health and safety rules
around the use of computer screens and glare from sunlight.
Minimise east-west exposure because of the low angles of the sun (when it rises and sets), and high variation of
sunlight levels (exposure for only half a day). The west elevation can suffer from large solar gain during the summer, but
contribute little solar gain during the winter.
Useful daylight (straight arrows) and unwanted glare (jagged arrows) on different faces of a building
Fig5. Useful Daylight And Unwanted Glare (Source: Autodesk)
Treat each elevation differently do not use the same glazing for all elevation for example: minimise thermal
transmission on the northern elevation and minimise solar gain in the west elevation.
Multiple buildings where a commercial development has more than one building on its site the following 3 basic
rules, will maximise the site for all occupants:
1. buildings with the greatest number of storeys should be on the NORTH side of the site, which minimises overshading;
2. progressively lower storey buildings should be located towards the SOUTH of the site;
3. parking, garages, sheds and other non-essential out buildings should be to the north of all buildings;
Landscaping consider existing trees and hedgerows when planning the layout of a site, as these can either provide
shelter thus reducing heat loss or can be detrimental and inhibit passive solar gain by obstructing sunlight or overshading, especially in winter when the sun is lower.
Natural ventilation building should be orientated to maximise prevailing winds to provide cooling breezes during the
summer, but avoid cold winds during the winter. This can be done by aligning the buildings short axis with the prevailing
winds. Aligning the long building axis with the prevailing winds is least affective.
Fig6. Orientation For Maximum Passive Ventilation (Source: Autodesk)
Overhangs overhangs should be in proportion to the glazing underneath. A correctly sized overhang will provide
shading during the summer, from the steeply angled, intense sun, whilst allowing penetration into the building from the
lower angled less intense winter sun.
Building form unlike dwellings, where the most efficient building shape minimises the surface area to volume ratio, as
more compact designs have less surface area from which to loose heat, commercial buildings want to maximise their
exposure to natural light. So whilst a cube tends to provide an almost ideal shape for a dwelling, a commercial building
H
U . Commercial buildings can be arranged as wings to
maximise use of land, with sufficient space between to avoid overshading. This works best with buildings over 10
storeys high.
Fig7. Cutouts In A Building's Footprint Can Provide Good Daylighting (Source: Autodesk)
Although cube shaped buildings are more thermally efficient, providing natural light into their interior is difficult. A
conflict arises between the additional cooling load from increased use of artificial lighting and the perimeter heating
load, which will require a complex (and costly?) HVAC solution.
Services are best placed in a central core, where natural lighting is not a factor or on the west elevation where natural
light levels are hard to control eg: lift shaft, stair well, electrical and other service cupboards.
The use of an atrium allows daylight to penetrate into the building core. When such a design is utilised, a cube shaped
building is generally more suitable to this design approach. It is important to not oversize the atrium as these enclosed
glazed spaces can rapidly heat up and make the building uncomfortably hot. A number of smaller atria or light wells may
provide a better solution than one large atrium.
Atrium should be designed as a naturally heated and cooled/vented space ie unconditioned, to reduce or eliminate the
cost of heating and cooling. It may be possible to have conditioned or partially conditioned entrance/lobby at the base
of the atrium.
Offices with windows facing out onto an atrium have the advantages of a similar office overlooking an external
courtyard but without the thermal losses and poor acoustic qualities.
Where possible, corner offices should have a double aspect or corridors/public areas should have windows on opposite
elevations. This provides better light distribution, but the design must consider any issues associated with the loss of
thermal performance of the building envelope.
Finally, multi-storey commercial buildings tend to have a deep envelope incorporating the frame, insulation, external
clad
within the building interior.
Eco Who - B
I
O T I
O B
O
Royal Institute Of British Architects - Information On Building Orientation
Sustainable Energy Authority Of Ireland - Passive Solar Heat
Woking Borough Council - Climate Neutral Development: Site Layout & Building Design
Technical Toolkit
User Behaviour
2.2.1.5
New Build
User Behaviour




o Retail AC 200-260
o Hotel AC 243-285
o Office NV 35-70
o Office AC 100-135
o On site RE
o Off site RE
o Off grid
The section will elaborate the interaction of user behaviour in relation to NZEB technology solutions.
In general, technological developments in the field of smart grids and their related marketable solutions increase energy
efficiency, resulting in a reduction in energy consumption. Effectively this is not always the case. Improvements of
technologies also influence consumer/user behavior. This often leads to increasing demand for services and solutions
that may have not been available before the technological developments took place. This increased demand leads to a
H
technological developments.
Several aspects should be taken into account and strategies have to be worked out in the implementation process of
NZEBs:

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
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

usage profiles, strategies to let the user be aware of energy consumption (metering, smart metering) and
mechanisms for energy saving (general introduction)
similarities and differences of consumption profiles due to different types of buildings
expertise on automated systems
knowledge, not only about energy efficiency of applications but also about new combinations of components
power-line and wireless technologies
applicable software solutions that enable the control of appliances with an open architecture paradigm
guidance/manuals and attendance/consultation by experts during startup and optimization of systems
(together with the user)
Besides building needs and system needs, user behaviour is the main aspect to ensure the estimated/expected
savings during implementation.
NZEBs include:
1. Passive components - no user activity and/or automated control systems needed (i.e. building envelope)
2. Active components - user activity and/or automated control systems needed (i.e. heating system, ventilation
system, sunshades...)
Complex automated technology systems require high level of expertise, instruction and regular maintenance. The
following questions will have to be discussed with homeowners (users) and system operators when trying to find the
appropriate automated solution for a NZEB.
 How deep do I want to go into high-technology systems? How much high-technology is practical?
 Which components (half-automated/automated systems) are visible and can be modified by users?
 Who is responsible for the maintenance of the system (owner/house management)?
Since the automation and technological decisions influence other aspects of a NZEB (i.e. building physics, building
design), it is recommended that the above questions be answered at an early stage of the planning process.
EnerBuild - User Habits, Impacts On Energy Consumption In Passive Houses
Useable Buildings
Non Domestic Building New Build
Technical Toolkit
Building Fabric
2.2.2
New Build
Building Fabric
NZEB Building Fabric




Minimise heat loss and therefore heat demand
Minimise thermal bridging
o Ensure continuous layer of insulation around the building fabric envelope
Maximum permitted U-values:
o Foundation/Ground floor = 0.13 W/m2k
o Walls = 0.12 W/m2k
o Flat roof & Pitched roof = 0.11 W/m2k
o Windows = 1.5 W/m2k
Maximum permitted Primary Energy Demand = varies for different building types
The building fabric relates to the elements and materials used to construct a building. The building envelope consists of
of the building. The aim of the building fabric is to create an acceptable level of thermal comfort for the particular use of
the building. Chartered Institution of Building Services Engineers Guide A, Table 1.5 gives criteria for thermal comfort
levels for a large variety of building types, such as airports, banks, schools, sports halls and hotels.
Approved Document L2A - Conservation of fuel and power in new buildings other than dwellings, outlines the design
characteristics that should be adhered to in order to minimise energy consumption. The calculated rate of CO2 emissions
from the building must not be greater than the Target CO2 Emissions Rate. It is critical to note that in order to adhere to
the above, the maximum values stated in the Part L must be bettered.
To reach NZEB standards, maximum permitted U-values for various building fabric elements have been suggested.
These are discussed in more detail for each building fabric element, and in the insulation section of this toolkit. The
maximum Primary Energy demand for non-domestic buildings for various building types has been discussed in Section
1.15: Practical Aspects.
Fig1. Energy Rating For Non Domestic Building (Source: Net Zero)
Heat Loss
When designing a building, it is important to remember that the building envelope must be durable, water tight,
structurally sound, secure, aesthetically pleasing and economic. However, it must also be built in such a way as to
reduce its energy requirements, by minimising heat loss in order to reduce the amount of energy required to heat the
home. The building fabric, therefore, must strike a balance between the different requirements in terms of thermal
comfort including ventilation and daylight, whilst also providing protection from thermal and moisture elements. The
fabric design is a major factor in determining the amount of energy a building will use during its lifetime.
T
A


C
D
ACD
Energy Performance Building Directive (EPBD, 2010)
Department Of Community & Local Government - Part L Accredited Construction Details
The heat loss (or gain) to a home through the building fabric is found by adding the fabric heat losses to the infiltration
heat losses.
Qtotal
Qfabric + Qinfiltration
Qfabric U A
Qinfiltration
W
C V
Where:
A = area of the envelope (m2)
0
C)
3
density of air (kg/m )
Cp = specific heat capacity of air (J/kgK)
V = air volume flow rate due to external wind pressure (m3/s)
V = Vol x N
3600
Where:
Vol = volume of the room (m3)
N = air change rate assumed due to external wind pressure (air changes per hour)
The equation for heat loss due to infiltration can be simplified to:
Qinfiltration = N V
Typical air change rates vary depending on the nature of construction and the exposure of the site. Values can be
obtained from CIBSE Guide A, Tables 4.13 - 4.21
Fabric Thermal Properties
The properties of the buildings materials will determine how that building will respond to the surrounding environment,
both internally and externally. There are two classes of construction fabric:


Opaque walls, roofs, floors etc.
Glazed windows, rooflights etc.
The fundamental properties of each building fabric element which affect the thermal properties of the material are
described in detail in Chartered Institution of Building Services Engineers Guide A and Chartered Institution of Building
Services Engineers Guide F, and include:








Density mass per unit volume.
Specific heat capacity
Thermal conductivity and resistance ability to conduct heat through its surface
Emissivity
Solar transmittance
Solar absorptance & reflectance
Thermal transmittance (U-values)
Thermal admittance (Y-values)
The thermal performance of the building fabric plays a vital role in whether a home is compliant with the building
regulations, in terms of its contribution to attaining the overall energy and emissions target by limiting heat loss. The
amount of heat lost through each element of the building fabric is shown.
Fig2. Heat Loss From Building (Source: Carbon Trust)
Thermal Comfort
Sections 1.2.2 and section 1.3 of Chartered Institution of Building Services Engineers Guide A discusses thermal
comforts, its components and what factors affect thermal comfort in a building. Although perception of thermal
comfort differs from person to person, there are guidelines that should be taken into account when designing
improvements to a home in terms of the main factors of thermal comfort, which are:





Temperature
Humidity
Air quality (velocity and freshness)
Lighting levels
Noise levels
Table 1.5 of Chartered Institution of Building Services Engineers Guide A outlines the parameters for thermal comfort
for varying building types, in terms of recommended acceptable temperatures, humidity, air changes, lighting levels and
noise levels.
U-Value
The thermal transmittance, or U-value is a measure of the rate of heat flow across or through the element, and is
measured in w/m2K. The higher the U-value, the greater the rate of heat flow through the material. It is based on the
conductive capabilities of materials as well as the thickness of the layer within the envelope. The U-value of each
element of the building envelope must be of a certain value to ensure minimum heat loss through the envelope, as per
Building Regulation document L2A.
Chartered Institution of Building Services Engineers Guide A, Chapter 3 contains Tables with thermal conductivity and
thermal resistances that can be used to calculate U-values. U-values for individual layers are then used to calculate an
overall U-value for bridged layers.
Fig3. Thermal Transmittance Through Multilayer Element
Y-Value
The thermal admittance, or Y-Value is the measure of the rate of heat flow between the internal surface of the building
and the air temperature of the room, and is measured in w/m2K. The thermal admittance of the material creates a time
lag between the heat transfer, which is determined by the materials nearest to the internal surface.
Fig4. Thermal Admittance Of Multilayer Element
Thermal Mass
The thermal mass of the building is the amount of heat storage capacity the building fabric has. The heat stored is used
when required to heat or cool a building. Thermal mass storage is best suited to buildings in a cold climate that are used
continuously, as it helps maintain a steady internal temperature. There are 2 elements that quantify thermal mass:


Specific Mass Total Mass of building / Floor are of building (kg/m2)
Response Factor related to the thermal admittance
Thermal Bridging
Thermal bridging occurs at any junction between building fabric elements, and can cause a reduction in internal
temperature and an increase in heat loss due to a break in insulation. There are two types of thermal bridging:
1. Repeating thermal bridges bridges that occur at regular patterns within the building element, by items such as
cavity wall ties, mullions, noggins, joists etc. This type of thermal bridge is included when calculating the U-value
of the building element
2. Non-repeating thermal bridges bridges that occur at junctions between elements such as walls, roofs and
floors, around doors and windows etc. The heat loss at these bridges are calculated separately
The images shown below show the importance of closing the thermal bridge. The orange colour around the window
(highlighted in green) shows the amount of heat escaping through the building envelope, due to incorrect insulation
around the window lintel, which has left a thermal bridge.
Fig5. Thermal Image Of Thermal Bridging (Source: MIT Field Intelligence Laboratory)
The Sustainable Energy Authority Ireland has developed a thermal bridging spreadsheet, allowing the thermal bridging
factor to be calculated:


SEAI Thermal Bridging Factor Application
SEAI Thermal Factor Spreadsheet Tool
There are a number of computer simulation programmes that can be used during the design stage of a building, in order
that different materials, thicknesses and layers can be tested to ensure the required design specification are met:
 IES VE (Virtual Environment)
 SBEM
 DEAP
Fig6. IES VE (Virtual Environment) Computer Simulation (Source: IES VE)
(Building Fabric Template calculates total U-value of the element, in this case an external wall)
Low Energy Architectural Research Unit - Information On Building Fabric CLEAR Project, (Comfortable Low Energy
Architecture)
Low Energy Architectural Research Unit - Basics Of Thermal Comfort
Department Of Community & Local Government - Part L Accredited Construction Details
Carbon Trust - Building Fabric Manual
Leeds University Low Carbon Housing Learning Zone - Information On Building Fabric
Leeds University Low carbon Housing Learning Zone - Information On Thermal Bridging
Sustainable Energy Authority Ireland - Thermal Bridging Calculation Tool
Video links:
Energy Quarter - Thermal Bridging
Energy Quarter - Air Tightness
Technical Toolkit
Foundations
2.2.2.1
New Build
Foundations (NBND)




The key part of building an energy efficient building is to minimise heat loss through the building fabric, including heat
lost through thermal bridges. The tying together of the foundation to the other building envelope elements is key, and
the construction of an uninterrupted insulation layer ensures elimination of thermal bridges.
Building Regulations Approved Document Part L Buildings Other than Dwellings does not specify a maximum permitted
U-value for foundations, although exposed floors have limit of 0.25W/m2K in both England and Wales. In terms of
Sustainco, in order to reach NZEB standards, it is suggested that a minimum U-value of 0.13W/m2k for foundations.
There are three main types of foundation construction types for non-domestic buildings:

Strip foundation foundation strips to carry the weight of load bearing structures/walls. They are used when
the soil has a good bearing capacity
o Construction Studies: Strip Foundations
Fig1. Strip Foundations (Source: Wilde Consulting Engineers)

Raft foundation where reinforced concrete is poured across the whole floor area of the building. They tend to
be used when soil bearing capacity is low, and there is a large load. The raft foundation spreads the load over a
wider surface area than the strip foundation allows.
o Construction Studies: Raft Foundations
Fig2. Raft Foundations

Pile foundation piles or columns of concrete are driven deep into the soil to provide support for a concrete
beam, similar to a strip foundation. These type of foundations are used when the bearing capacity of the surface
soil is insufficient to carry the load of the building
o Construction Studies: Piled Foundations
Fig3. Pile Foundations (Source: Panoramio)
Edge insulation between the external wall and the ground floor slab is required to ensure a continuous insulation layer.
However, Chartered Institution Of Building Services Engineers Guide A states that, where the thermal conductivity of
the foundation is less than that of the soil type, the foundation wall can be treated as a vertical edge insulation block, as
shown in the image below. In this instance no separate edge insulation is required.
Fig4. Solid Ground Floor With Vertical Edge Insulation (Source: CIBSE Guide A)
Fig5. Solid Ground Floor With Foundation Wall Having Thermal Conductivity Less Than That Of The Ground (Source:
CIBSE Guide A)
Current building regulations, Part A Structural Safety, outlines the design specifications for standard foundations.
However this does not take into account any insulation or closing of thermal bridges. There are a number of accredited
design details, outlining approved methods of building the foundation and external walls in such a way as to eliminate
the thermal bridges:

PassiveDesign.org: Passive Foundations
In order to better these standards and reach a lower U-value of 0.13W/m2k, more insulation or insulation with higher
resistivity should be used. Foundation Insulation is discussed in more detail in Section 2.2.3.1: Foundation Insulation.
Chartered Institution Of Building Services Engineers - Guide A: Environmental Design
PassiveDesign.org - Passive Foundations
Homebond - House Building Manual
Technical Toolkit
Floors
2.2.2.2
New Build
Floors (NBND)




This section outlines the types of typical floor constructions, as well as providing information on where to find the most
relevant guides and regulations for correct construction methods.
Ground Floor
There are three main types of ground floor construction:

Solid concrete slab serves as both a foundation and ground floor. A mass of concrete, generally poured as a
large mass slab directly onto the ground
1. Concrete block/ innerwall; 2. Outside wall; 3. Hardcore infill; 4. Damp-proof membrane;
5. Sand blinding; 6. Min 100mm concrete
Fig1. Solid Concrete Slab (Source: www.homebuilding.co.uk)

Suspended concrete slab pre-cast concrete slabs, supported by bearings to allow suspension above the ground
1. Concrete block; 2. Outside wall; 3. Concrete block/ inner wall; 4. Sleeper wall;
5. Concrete beam
Fig2. Suspended Concrete Slab (Source: www.homebuilding.co.uk)

Suspended timber floor joists stretch from wall to wall, or are supported by concrete ring beams. Timber floor
boards or decking are laid over the joists.
1. Metal joist hanger; 2. Herringbone strut; 3. Outside wall; 4. Concrete block inner wall;
5. Concrete oversite; 6. Wooden joist
Fig3. Suspended Timber Floor (Source: www.homebuilding.co.uk)


Concrete or Timber Floor
Floor Structure Guide
Similar to the foundation, insulating the ground floor must be done in such a way as to create an uninterrupted
insulated layer with the external environment, in order to eliminate thermal bridges. Heat loss through a ground floor is
discussed in Chartered Institution of Building Services Engineers Guide A, Section 3.5, and depends on:
 Soil type
 Thickness of slab
 Ratio of perimeter to area
The three floor construction types are insulated in different ways, as discussed in more detail in Sections 2.2.3.2:
Ground Floor Insulation and 2.2.3.3: First Floor Insulation:
1. Solid concrete slab insulation between slab and soil
2. Suspended concrete slab insulation between concrete slab and screed floor
3. Suspended timber floor insulation between joists
Building Regulations Approved Document Part L Buildings Other than Dwellings specifies a maximum permitted Uvalue for exposed floors of 0.25W/m2K in both England and Wales. By calculating the U-value of the ground floor in its
steady state using the heat loss calculations, the amount of insulation required to meet the permitted U-values can be
found. I.S. EN ISO 13370: 2007 deals with the calculation of U-values of ground floors.
In terms of Sustainco, in order to reach NZEB standards, it is suggested that a minimum U-value of 0.13W/m2k for
foundations. This can be reached by increasing the depth of insulation or increasing the thermal conductivity of the
insulating material. This is explained in more detail in Section 2.2.3.2: Ground Floor Insulation and Section 2.2.3.3: First
Floor Insulation.
Intermediate Floors
Internal floors tend to be timber floor construction, although occasionally concrete floor construction will be used. Heat
loss and transfer through internal floors differ from ground floors in terms that the ground floor heat is lost from the
internal area of the building to the external environment. In comparison, heat is transferred through first and
subsequent floors and circulated within the internal environment, and therefore heat transmission tends to be from
one heated space to another. The difference in temperature between heated spaces dictates the amount of heat flow
between the spaces, as discussed in Section 2.2.2: Building Fabric.
Similar to ground floors, the amount of insulation required for internal floors, in between timber joists, depends on the
exposed perimeter to floor area ratio. In order to ensure different heating zones within the building, insulation is still
required between internal partitions and floors; the difference being that the temperature difference between internal
zones is much lower than the temperature difference between external and internal zones, therefore depths of
insulation can be decreased.
The critical issue is again to eliminate thermal bridges between the intermediate floors and other elements of the
building fabric, specifically the building envelope.
Fig4. Timber Intermediate Floor (Source: Government of Ireland)
There are a number of accredited design details, outlining approved methods of building the ground and
internal/intermediate floors in such a way as to ensure thermal continuity and air tightness:


PassiveDesign.org: Passive Foundations
UK Part L ACD
International Organisation For Standardisation - ISO 13370:2007 Thermal Performance Of Buildings, Heat Transfer Via
The Ground
Passive Design - Foundation Design Details
Building Regulations Approved Document L2A
Chartered Institution of Building Service Engineers - Guide A Environmental Design
I Brick - Information On How The Different Floor Construction T
C
T
F
Technical Toolkit
Walls
2.2.2.3
New Build
Walls (NBND)




This section outlines the types of wall construction, as well as providing information on where to find the most relevant
guides and regulations on the correct types and construction methods to be used.
External Walls
The external walls of a building typically make up the largest percentage of the building envelope. It is, therefore open
to the most heat loss due to the large area of exposed surface. Eliminating cold bridges and limiting air permeability is
key to reducing heat loss through this part of the building fabric.
Due to the many different types of non-domestic buildings, their use, location and aesthetics, external wall construction
can vary greatly. However, the maximum permitted U-values and maximum permitted primary energy demand for each
building type must not be exceeded.
Fig3. Zinc Aluminium Clad Building (Source: Archi Expo)
Despite the many finishes to a building fabric envelope, there are 3 main construction types for external walls. Consult
ACD
Section 2.2.2: Building Fabric:

Cavity block/masonry wall the main aim is that the cavity prevents moisture movement from the outer leaf to
the inner leaf. The cavity can be filled with an insulation material to improve the U-value of the overall external
wall construction.

Solid block/masonry wall traditional form of construction, used for the thermal mass properties as the wall
thickness tends to be much greater.

Timber frame wall with external masonry leaf
Building Regulations Approved Document Part L Buildings Other than Dwellings specifies a maximum permitted Uvalue for Walls 0.35W/m2K in both England and Wales. To reach NZEB standards In the UK, SustainCo is suggesting
maximum U-Value of 0.12W/m2k. This can be reached by increasing the depth of insulation or increasing the thermal
conductivity of the insulating material. This is explained in more detail in Section 2.2.3.4: Wall Insulation.
Internal Walls
Similar to intermediate floors, heat loss between internal walls depends on the heat difference between internal spaces,
which is generally smaller than the differential between external and internal environments. Therefore, the use of each
space should be taken into consideration during the design phase, to ensure that correct construction type and levels of
insulation is used.
Depending on the type and aesthetics of a non-domestic building, internal walls can vary greatly, and building fabric will
be specified by the design team. Depending on the load expected to be taken by the internal wall, structure type will
vary between concrete block with plaster finish, to timber or steel frame with plasterboard internal stud walls, or even
glazed interior walls. Building Regulations. Part A: Structure and Part L2A: Buildings Other Than Dwellings should be
adhered to.

Stone finished interior wall
Fig4. Stone Finished Interior Wall (Source: Property24)

Glazed & steel partition walls
Fig5. Glazed And Steel Partition Walls (Source: Wall & Celling Solutions)
International Organisation For Standardisation - ISO 13370:2007 Thermal Performance Of Buildings, Heat Transfer Via
The Ground
Passive Design - Walls Design Details
Building Regulations Approved Document L2A
Chartered Institution of Building Service Engineers - Guide A Environmental Design
Technical Toolkit
Walls
2.2.2.3
New Build
Walls (NBND)
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This section outlines the critical features in relation to doors and windows in relation to creating energy efficient
buildings. Similar to other building fabric sections, the importance of eliminating thermal bridges is key. Typically, in the
past the areas around windows and doors were left un-insulated, or gaps were left between layers, causing thermal
bridges where heat could easily escape. New building regulations have ensured that stricter attention be paid to the
areas around windows and doors, as well as ensuring higher U-values for these external building envelope elements.
The amount of glazing in a non-domestic building can account for a significant amount of the building fabric, as
aesthetics of a building win out. Therefore the U-value of the windows plays a much larger role than in a domestic
building. All windows and doors should adhere to EN Standards 12207: Windows & Doors Air Permeability, in order to
ensure air tightness and therefore reduce heat loss.
Fig1. Glass Front On Non Domestic Building (Source: Archie Expo)
Building Regulations Part L2A gives maximum elemental U-values for pedestrian doors and windows as 2.2W/m2K.
Windows
Windows have a number of functions in a building;
1. Form part of the building envelope
2. Allow in natural light
3. Allow heat losses and gains
4. Allow natural ventilation
Heat is lost through windows in a number of ways, as shown in the figure below. About 2/3 of the heat loss is due to
radiation through the glazing element of the window, which is dependent on the U-value. The next largest area of heat
loss is air leakage from around the frame that is the thermal bridge that exists. Therefore, it is crucial to minimise the
U-value of the window and eliminate thermal bridges by ensuring a continuous insulation layer.
Fig2. Heat Loss Through Windows (Source: Green Spec Archie Expo)
In Ireland, the size and position of windows has become a much more important aspect of the initial design of a building
in order to maximise the heat gains and natural light entering, whilst minimising heat loss through the glazed elements
of the structure. However, thermal discomfort due to solar overheating must also be avoided. Therefore, the correct
balance between glazed and opaque structure must be found during the design stage.
For NZEB standards to be reached, maximum permitted U-values should not exceed 1.5W/m2k
The size or area of glazing for day-lighting is outlined in detail in BS 8206: Part 2: 2008 Code of Practice for Daylight and
CIBSE Lighting Guide LG 10. See Section 2.2.7.3 of these toolkits on Daylighting for further design guides.
Solar shading may be also be required to avoid overheating due to solar gains. There are various types of shading that
can be applied including:
 Overhangs/Canopies
 Light shelves
 Louvres (fixed and moveable)
 Shutters
 Vertical fins
 Trees and vegetation
Fig 3, 4 And 5. Solar Shading (Sources: WIT, AECOM & ArchiExpo)
The orientation of the window will play a part in the most suitable type of shading required. For northern hemisphere
buildings, the general rule of thumb is:
North - None required
East - Vertical shading/Louvres (moveable)
South - Fixed horizontal shading
West - Vertical shading/Louvres (moveable)
More information on Solar Shading Design:
CIBSE TM37: Design for Improved Solar Shading Control
Carbon Trust: CTL065 How to Implement Solar Shading
There are different types of glazing that can be used in the windows in order to reach the desired U-values and design
criteria. Generally in Ireland single glazed has become obsolete and double and triple glazed windows are usually used.
Similarly, double and triple glazed windows can come with a gas filling, such as argon or krypton. This gas acts as an
insulator, and therefore produces more energy efficient windows than air filled double and triple glazing.
Doors
External doors have one main function they are the opening in which users access a building. The external door forms
part of the building envelope, and is similar to windows in the way in which heat is lost through them. However, in the
UK, the main method of heat loss through an external door is every time the door is opened.
Therefore, similar to windows, it is critical to ensure that U-values are low, and that the thermal bridges are eliminated.
Another good aspect of design to reduce heat loss through the door is to create a porch area, or draught lobby. This
creates an extra zone between the internal living quarters and the external environment, reducing the temperature
differential between zones.
Fig6. Draught Lobby (Source: MFM Joinery)
US Dept. of Energy: Window Types
Carbon Trust: Building Fabric
Energy Saving Trust: Energy Efficient Windows
USA Efficient Windows Collaborative
US Dept. of Energy: Doors
European Standards - EN Standard 12207 Windows & Doors Air Permeability
British Standards Institute - BS 8206: Part 2: 2008 Code Of Practice For Daylight
BFRC T UK
E
E
W
Technical Toolkit
Roof
2.2.2.5
New Build
Roof (NBND)
NZEB Building Fabric (NBND)
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This section outlines the different building fabric elements in a roof construction. The roof is the final element of the
building envelope, closing the building off to the external environment. Approximately 20% of all heat loss is through
the roof structure.
Any part of a roof that has a pitch greater than 70% is treated as a wall, and therefore is not included in this section of
the toolkit. Please see Section 2.2.2.3: Walls for more details.
There are 2 types of roof constructions:


Pitched roof
Flat roof
Fig1. Non Domestic Roof (Source: Alumasc)
Fig2. Non Domestic Roof (Source: Structurae)
Building Regulations Part L1A
0.25W/m2k.
Buildings Other than Dwellings states that the maximum permitted U-value for a roof is
To reach NZEB standards in the UK, SustainCo suggests that the maximum permitted U-values for roofs is 0.11W/m2/K
for both pitched & flat roofs.
Thermal bridges at roof and external wall junctions should be eliminated by ensuring a continuous insulation layer.
Acceptable construction methods should be used to successfully create this continuous insulation layer, dealing with
each type of wall construction type, as discussed in Section 2.2.2.3 Walls.
Roofs or parts of the roof can also be unheated spaces, as in figure 3. An unheated space will affect the amount of heat
loss between spaces, depending on the difference between temperatures between spaces.
Fig3. Room In Roof Insulation (Source: TrainEnergy)
Carbon Trust - Building Fabric
Carbon Trust -How To Implement Roof Insulation
Energy Saving Trust - Roof And Loft Insulation
Technical Toolkit
Insulation
2.2.3
New Build
Insulation
NZEB Insulation (NBND)
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o Ensure continuous layer of insulation around the building envelope
Maximum permitted U-values =:
o Foundation/Ground floor = 0.13 W/m2/k
o Walls = 0.12 W/m2/k
o Flat roof & Pitched roof = 0.11 W/m2/k
o Windows = 1.5 W/m2/k
Thermal insulation is part of the building fabric that minimises heat loss through the building envelope as discussed in
Section 2.2.2 B
F
A
heating, according to the
Sustainable Energy Authority Ireland. Therefore, one way to reduce energy consumption is to ensure that heat loss is
kept to a minimum by maximising the insulation in a building.
There are many types of insulation, and this section will outline insulation types and correct installation methods for
each element of a building. As discussed in the section on building fabric, it is critical that the insulation layer is installed
in such a way as to ensure a continuous layer so as to eliminate thermal bridging.
Fig1. Heat Loss From A Badly Insulated House (Source: LowEnergyHouse)
The thermal performance of the building fabric plays a vital role in whether a home is compliant with the building
regulations, in terms of its contribution to attaining the overall energy and emissions target by limiting heat loss. The
amount of heat lost through each element of the building fabric is shown in the figure below. To minimise heat loss, the
U-value of a building element should be minimised, as outlined in building regulations approved document part L2a.
This was discussed in detail in Section 2.2.2: Building Fabric.
In general, to decrease the U-value of building element, increase the thickness of insulation installed. However, in line
with Nearly Zero Energy Building philosophy, the cost optimal solution must be applied. There will become a stage
where simply adding to the thickness of the insulation will not decrease the heat loss through the building element to a
significant degree.
Fig2. Building Heat Loss (Source: Carbon Trust)
Types Of Insulation
Before the most suitable type of insulation can be chosen, the following should be determined:


Where the insulation is required/needed
The recommended elemental U-values for areas you want to insulate
Once this is known, the type and thickness of insulation required to reach the recommended U-values can be calculated,
using methods discussed in Section 2.2.2: Building Fabric.
Blanket Insulation most common form of insulation, also known as batt and roll. Usually fibreglass materials,
insulation comes in blankets which can be rolled out between joists in an attic or between studs in a wall.
Fig3. Loft Insulation (Source: Waterworks Valley)
Loose-fill / Blown Insulation small particles of foam or fibre that can be blown into any space, and can take on the
form and shape of any space, making it ideal insulation solution for hard to reach areas.
Fig4. Blown Insulation (Source: ArchiExpo)
Concrete Block Insulation used to build insulated walls and foundations, the centre of the hollow block can be filled
with insulation to increase the R-value.
Fig5. Concrete Block Insulation (Source: ArchiExpo)
Polyurethane Spray Foam is a fast, cost effective insulation treatment that can be applied internal or externally. Spray
foam is equal or slightly superior to insulation batts or loose fill insulation particles. Spray insulation generally comes in
two formats i) low density open cell insulation, ii) medium density closed cell insulation.
Fig6. And Fig7. Polyurethane Spray Foam (Source: McGraw)
Rigid Board / Sheet Insulation
walls to roof.
rigid panels of insulation, can be used to insulate any part of a building, from floors, to
Fig8. Sheet Insulation (Source: Hendricks Architecture)
US Dept. Of Energy - Insulation Materials
US Dept. Of Energy - Types Of Insulation
Department Of Community & Local Government (UK) - Approved Document Part L2a: Conservation Of Fuel & Energy,
New Buildings Other than Dwellings
Department Of Community & Local Government (UK) - Part L Accredited Construction Details
Carbon Trust Building Fabric
Energy Savings Trust Insulation
Technical Toolkit
Foundation Insulation
2.2.3.1
New Build
Foundation - Level Insulation
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Foundation-level insulation is a relatively new concept in the UK and is used in the construction of new low-energy
buildings. Traditional foundations consist of pouring the specified concrete mix into previously prepared trenches.
Insulation is only added to the sub-structure when the floor slab is being constructed, or if the mass-pour concrete also
forms the walls of a basement area.
Why Is Foundation-Level Insulation Required?
There are a number of reasons for insulating at foundation level:
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The elimination or reduction of thermal bridging through the sub-structure and external envelop
An insulated foundation, can act as a heat sink and help even out variations in temperature
The insulation layer can act as a waterproof barrier
By regulating the temperature of the foundations, insulation can reduce thermal movement in the substructure, thus minimising the formation of cracks and preventing radon from seeping into the sub-structure

In building with a basement, un-insulated foundations may account for up to 50% of the total heat loss
(assuming an airtight construction)
Thermal Bridging
Thermal bridging is the loss of heat through the building envelop where there is a break in the insulation layer or a
differential in the resistance value of adjoining building elements. Thermal bridging can account for up to 15% of the
heat loss in a building, and becomes progressively worse the higher the overall insulation levels are, as the thermal
bridge gets colder and more heat is transferred.
Fig1. Thermal Bridging (Source: Viking Insulation)
Dew Point
In northern European countries where the temperature drops below 70C for a significant period of the autumn/winter
seasons, the edge of foundations and a concrete floor slab are vulnerable to the formation of interstitial condensation
caused when the dew point falls within the sub-structure, and moisture condenses out of the atmosphere into the
fabric of the foundations and slab. This can cause potential problems with reinforcing bars, where their carbonisation
causes concrete to disintegrate leading to the loss of structural integrity.
Relative humidity
Even in European countries where the dewhumidity in the sub-structure to increase, where there is a temperature difference between the relatively
sounding ground and the relatively
foundations (caused by thermal bridging). If this reaches a range above
60%, it is possible for mould and fungus to grow and spread into the habitable area of a building.
This scenario is very likely in a low energy building which has a high degree of airtightness.
Frost Heave
Frost heave is a potential problem in northern European countries due to prolonged winters. Such heave is cause by a
combination of wet soils, ground penetrating sub-freezing temperatures, and susceptible soil type. This has been largely
eliminated now by building regulations in affected countries and the use of specialist insulation systems see below.
Fig2. Frost Heave (Source: Oikos)
How Is Foundation - Level Insulation Achieved?
Foundation-level insulation of a very basic design can consist of suitable insulation materials placed against the outside
face of a mass poured foundation to provide a crude, thermal layer. This design will provide minimal insulation but will
not fully address issues with thermal bridging or deal with the problem of high relative humidity as discussed above.
This design can be used with a retrofit project, as the wrap-around systems discussed below are only suitable for newbuild projects.
Fig3. Insulation Materials Placed Against The Outside Face Of A Mass Poured Foundation (Source: Green Show Case)
Low energy buildings tend to be designed and constructed with a
significant advantages over the traditional mass pour concrete foundations and slab:
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foundation. This has a number of
They are on a par with the cost of traditional foundation
They tend to use approximately 50% less concrete than traditional foundations this results in a smaller carbon
footprint
They can be used with all ground conditions
They can provide or accommodate a radon barrier
Can be used with under-floor heating systems
They will tend to provide the lowest U-values
They remove thermal bridging between the foundation and walls
They remove the risk of condensation in walls at low level cause by thermal bridging
Currently, there are a number of proprietary insulated foundation systems that are used in the construction of low
energy buildings, primarily houses. All use Expanded Polystyrene (EPS) which has:
i)
ii)
iii)
very good insulation levels
high compression strength
low water absorption
Fig4. Insulation Of A Floating Slab Foundation (Source: Hanse)
Fig5. External Insulation To A Concrete Foundation, Where The Foundation Forms A Basement Area (Source: APSA)
The designer has free rein to consider the various systems available in their local market. Looking at systems available in
the wider European market, may require the expertise to install such systems is also be imported, which may prove cost
prohibitive.
The specialist companies who will install the insulation will be familiar with the various criteria required to provide
maximum benefit. However, the designer should look at the areas where thermal bridging has the greatest potential,
and ensure the necessary correct detailing is provided, in particular:
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at the corners of foundations because of the combined heat loss from two sides
where door thresholds cross the foundation line and there is a break in the insulation layer
where any services cross into the building, through the foundations or the floor slab
Passive Design - Information On Foundation Level Insulation For Passive Standards
Building Science - Slab Edge Insulation
CIBSE - Guide A: Environmental Design
Homebond
Technical Toolkit
Ground Floor
Insulation
2.2.3.2
New Build
Ground Floor Insulation
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Ground floors are usually either solid concrete slabs or suspended timber/concrete beam floors. As part of the building
envelope, improving the thermal efficiency of the ground floor will save energy, reduce heating costs and provide a
more comfortable environment for building users. Depending in the ground floor system used, the position of the
insulation will vary.
Why is Ground Floor insulation required?
The main reason to insulate a ground floor on of a building is to eliminate thermal bridging and to make the internal
environment more comfortable.
Thermal Bridging this is the loss of heat through the building envelop where there is a break in the insulation layer or a
In the case of a concrete slab, insulation will also help eliminate or reduce interstitial condensation.
Dew Point in northern European countries where the temperature drops below 7ºC for a significant period of the
autumn/winter seasons, the edge of foundations and a concrete floor slab are vulnerable to the formation of interstitial
condensation caused when the dew point falls within the sub-structure, and moisture condenses out of the atmosphere
into the fabric of the foundations and slab. This can cause potential problems with reinforcing bars, where their
carbonisation causes concrete to disintegrate leading to the loss of structural integrity.
Relative Humidity even in European countries where the dewfor the relative humidity in the sub-structure to increase, where there is a temperature difference between the
I
a range above 60%, it is possible for mould and fungus to grow and spread into the habitable area of a building.
How is Ground Floor insulation achieved?
Suspended Concrete Floors
There are four methods of insulating suspended concrete floors:
1) Use a proprietary insulation slab on top of a generic block and beam or pre-cast concrete flooring system
After the block and beam structural deck is put in place, grout or levelling topping is applied, before a radon
barrier is rolled over the flooring and into the wall cavity. The proprietary insulation slab should be laid on the
levelling topping with a polythene separating layer under the finished screed to prevent moisture movement
into the board junctions.
Insulation boards should be cut and butted tightly together, to give a continuous layer across the whole floor.
The under-floor void should be vented to prevent damp problems.
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QuinnTherm
Jablite
2) Use a proprietary insulated pre-cast concrete flooring system
These precast insulated units are similar to traditional concrete flooring systems, except they are delivered to
site, with integrated EPS insulation in the waffle soffit. They form a deep unbroken insulation layer across the
entire floor.
Fig4. Proprietary Insulated Slab Under A Reinforced Concrete Floor (Source: CHC TETRiS Floors)
4) Use a proprietary insulated block and concrete beam system
This is similar to a concrete block and beam system, but the concrete blocks are replaced with EPS blocks. The
EPS
O
the flooring is complete, a structural topping reinforced with polypropylene fibres is poured and floated to a
finish.

Hanson Jetfloor
Solid Floor
For a solid concrete slab, insulation can be placed above or below the slab. As with suspended flooring, the key is to
avoid thermal bridging, by ensuring the floor and wall insulation are continuous.
All systems can incorporate a radon barrier, reinforcing mesh and under-floor heating.
Issues to be considered:
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Where possible, provide ground floor insulation in conjunction with insulated foundations to eliminate thermal
bridging
Do not block any sub-floor vents which are used to prevent condensation from forming on the cold side of the
floor
It is important to protect the integrity of the buildings air-tightness
Try and ensure continuity of the thermal barrier
Ensure the compressive strength of any insulation is sufficient to bear the load of the floor slab and any objects
or activity which will be placed upon the finished floor
The floor slab detailing to include a vapour control layer
Local regulations may apply to work for work associated with retro-fitting insulation to existing ground floors

If possible use renewable or recycled materials for insulation to reduce carbon footprint
Building Science - Information Sheet On Slab Edge Insulation
English Heritage - Energy Efficiency In Historic Buildings Insulating Solid Ground Floors
Low Energy House - Concrete Floor Insulation
Low Energy House Timber Floor Insulation
Super Homes How To Insulate Floors
National Insulation Association - Case Study On Low Energy House Refurbishment
Paroc Insulation Theory
Rebel Energy - Energy Efficient Best Practice In Housing
Technical Toolkit
First Floor Insulation
2.2.3.3
New Build
First Floor Insulation
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Maximum permitted Primary Energy Demand = varies for different building type
Because of the variety of non-domestic building types, designers can use one of a number of options to provide
intermediate floor:
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pre-stressed solid concrete slabs;
concrete beam and block;
shallow steel decking with a structural screed;
steel frame with structural screed
structural timber joists and sheeting
These forms of intermediate flooring give designers the ability to provide open spaces that can be sub-divided by future
owners or tenants.
Fig1. Intermediate Flooring (Source: Steel Floor Systems)
The various forms of intermediate flooring all serve the same function, which is to divide the building users from each
other or to separate different the building functions from one another e.g.
The choice of flooring system is decided upon by a number of factors. A designer should conduct a cost benefit analysis
against competing systems looking at the following:
 Final use of building;
 Speed of installation;
 Familiarity with the system;
 Delivery lead-in;
Ultimately, the flooring system adopted should be the simplest solution that meets the various project requirements.
Why Is First Floor Insulation Required?
The main reason to insulate an intermediate floor on a building project is to eliminate thermal bridging and to make the
internal environment more comfortable.
Thermal Bridging this is the loss of heat through the building envelop where there is a break in the insulation layer or a
How Is First Floor Insulation Achieved?
A new form of block and beam, uses EPS panels moulded around two integral steel beams. This system ensures the
insulation layer is continuous with no thermal bridging spots. It is compatible with underfloor heating and can reduce
the dead mass of the floor load by up to 50%, allow for an increase in building height without the penalty of having to
thicken or engineer the building envelope.
Fig2. Cross-Section Through A Quad-Lock Floor (Source: Quad-Lock)
Fig3. Comparison Of The Quad-Lock Floor System With A Traditional Mass Concrete Slab
(Source: Quad-Lock)
Shallow steel decking used in steel framed buildings, offers the benefit of being able to sit on the upper surface of the
bottom flange, to give a clean, shallow soffit profile, with no downstand beams dropping into the floor below. It may be
possible to integrate water ducts within the floor slab to help remove any heat that accumulated during the day.
Fig4. Installed Shallow Decking Sitting On The Top Of The Bottom Flange (Source: Steel Floor Systems)
Fig5. Shallow Deck Sheet Flooring Detail Structural Screed And Insulation On Top (Source: Steel Floor Systems)
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Do not block any sub-floor vents which are used to prevent condensation from forming in the void
Remember to protect the integrity of the buildings air-tightness
Try and ensure continuity of the thermal barrier
Local regulations may apply to work involving party walls for work associated with retro-fitting insulation to
intermediate floors
If possible use renewable or recycled materials for insulation to reduce carbon footprint
Local regulations may contain stipulations regarding fire rating of the type of insulation used
Passive Design - Information On Foundation Level Insulation For Passive Standards
Building Science - Information Sheet On Slab Edge Insulation
National Insulation Association - Case Study On Low Energy House Refurbishment
Eco Builders Floor Insulation
David Darling Encyclopaedia Floor Insulation
US Dept. Of Energy - Where To Insulate In A Home
Technical Toolkit
Wall Insulation
2.2.3.4
New Build
Wall Insulation
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This section outlines key aspects of wall insulation, as well as providing information on where to find the most relevant
guides and regulations on the correct types and methods of installation.
The external walls of a building typically make up the largest percentage of the building envelope. It is, therefore open
to the most heat loss due to the large area of exposed surface. Eliminating thermal bridges and increasing the elemental
U-value of the wall construction is key to reducing heat loss through this part of the building fabric. When insulating a
wall the desired U-value can be calculated to ensure building standards are adhered to see Section 2.2.2.3: Walls for
more details.
Broadly speaking, non-domestic buildings are insulated using one of three methods:
 Internally where the insulation is on the inside of the building frame/structure
 Cavity where the insulation is spray onto a structure before being clad;
 Cavity where the insulation is placed between the building frame/structure and cladding finish

Structural where insulation forms part of the building structure
It is critical that ventilation, air infiltration and moisture movement is taken into account when insulating any building.
Insulation should not be applied without appropriate consideration of the existing structure and the Building Physics of
the property. An inappropriately designed scheme can introduce new significant issues such as condensation and mould
growth, which will impact on air quality and may cause structural damage.
Internal Insulation
Internal insulation, also known as dry-lining, is where a layer of insulation is added to the inside of a building or house. It
is usually used when there is a solid wall, where there is no cavity to fill.
There are two main methods of internally insulating a wall:
1. Rigid insulation boards or plaster boards can be mounted directly onto the wall
Fig1. Rigid Internal Wall Insulation (Source: Easy Board)
2. Construction on stud-work frame and filling between studs with insulation material
Fig2. Internal Wall Insulation Using A Stud-Work Frame (Source: Super Homes)
External Insulation
External wall insulation is where the insulation layer is placed around the external layer of the building. Similar to
Internal Wall Insulation, it is used for solid wall construction types where there is no cavity that can be filled. It can also
be used in addition or instead of cavity wall insulation. It is more thermally efficient that internal insulation, and does
not affect the internal floor area. However it is generally much more expensive to install.
Fig3. External Wall Insulation (Source: Wallinsulation.ie)
There are typically two methods of fixing external insulation:
1. Single skin the insulation is fixed (mechanical or stuck) directly to the external surface of an outer wall, with
subsequent layers of reinforcing, render and decorative finish;
2. Cavity the insulation is fixed to the external wall surface but a frame is used to provide a ventilated cavity
behind an external cladded façade;
Masonry cavity walls with a partially filled cavity will cause a problem called Thermal Looping, which will isolate the
external insulation and prevents the entire wall from working as a system. The problem can be resolved by filling the
cavity prior to applying the external insulation.
Cavity Wall Insulation
Cavity wall insulation is where the cavity between block-work is filled with an insulating material. This can be either
installed during construction, using rigid insulation board or other insulating material. Alternatively, cavity walls can be
pumped with an insulating bead material.
Take note that insulation must be fitted correctly to avoid sagging and to ensure a continuous thermal layer around the
building envelope. Wall ties should be used, and must be kept clear of all debris such as mortar, to avoid moisture
movement through the layers.
Fig4. Rigid Cavity Wall Insulation (Source: AE Energy Solutions)
Fig5. Beaded Cavity Wall Insulation (Source: Ecowise Insulation)
Energy Savings Trust - Information on wall insulation
Energy Savings Trust - Choosing Internal Wall Insulation
Energy Savings Trust - Cavity Wall Insulation
Energy Savings Trust - Choosing External Wall Insulation
National Insulation Association
Carbon Trust - Cavity Wall Insulation
Solid Wall Insulation Guarantee Agency
Cavity Insulation Guarantee Agency
Which Cavity Wall Insulation
Technical Toolkit
Windows and Doors
2.2.3.5
New Build
Windows and Doors
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
This section outlines the critical features in relation to insulation around and U-values of doors and windows. Similar to
other insulation sections, the importance of eliminating thermal bridges is key. Typically the areas around windows and
doors were left un-insulated, or gaps were left between layers, causing thermal bridges where heat could easily escape.
New building regulations have ensured that stricter attention be paid to the areas around windows and doors, as well as
ensuring higher U-values for these external building envelope elements.
All windows and doors should adhere to European Standards EN Standards 12207: Windows & Doors Air Permeability,
in order to ensure air tightness and therefore reduce heat loss.
When determining the energy efficiency of a window or glazed door, designers must consider three factors that
influence thermal performance:
 U-value;
 Solar gain coefficient or G-Value;
 Air leakage through the windows gaskets and beads;
U-Value this is the measure of the amount of heat energy transmitted by convection, conduction or radiation through
a window or glazed door. The lower the U-value, the lower the windows ability to transmit heat energy.
To calculate the true U-value of a window or glazed door, each element that makes up the unit must be included in the
calculation eg the frame, any reinforcing in the frame, the glazed unit and any gas in the void between multiple panes of
a glazed unit.
The component of the window that makes the most significant contribution to its thermal performance is the glazing.
An array of glass coatings, multiple panes and cavity gases provide designers with a range of glass units with a
performance from 6W/m2K to 0.5W/m2K.
Fig1. Heat Loss Reduction (Source: REHAU)
Solar Gain Coefficient / G-Value This figure is a measure of the glazed units ability to re-radiate heat absorbed from
solar energy into a room. These figures can be obtained from the manufacturer.
Air Leakage This is given as an L50 value and is a measure of the amount of air leakage lost through a window at a
pressure of 50Pa. Manufacturers have to submit their products for independent testing.
Window Energy Performance (WEP) Certificate
T BF‘C S
UK
rating the energy efficiency of windows and is recognised within the
Building Regulations as a method to show compliance for your replacement windows installation.
Window Energy Ratings use a consumer-friendly traffic-light style A-E ratings guide simila
Fig.2 Window Energy Performance Certificate (Source: BFRC)
The label will display the following information:
1. The rating level A B C
2. The energy rating eg. -3kWh/(m²·K) in this example the product will lose 3 kilowatt hours per square metre per year.
3. The window U value eg. 1.4W/(m²·K)
4. The effective heat loss due to air penetration as L
eg. 0.01 W/(m²·K)
5. The solar heat gain eg. g=0.43
Windows
As with all elements of the building envelop, it is crucial to minimise the U-value of the window and eliminate thermal
bridges by ensuring a continuous insulation layer as previously discussed.
In non-domestic buildings, the fenestration design of windows, entrance doors and skylights can have a profound effect
on the design of the HVAC system. It is estimated an effective fenestration design can save between 10%-40% on
lighting and HVAC operating costs.
Window assembly materials and the physical installation all play a significant part in how effective overall they are in
transmitting energy and prevent air leakage. Manufacturers are investing significant sums in R & D, to further develop
window performance. Multi-panes glazed units, low conductivity gas between the panes and low-e coatings all
contribute to achieving this goal.
The demand for triple glazed, gas filled units in non-domestic buildings is growing as building developers react to the
demand from potential owners and tenants to keep operating costs down by improving thermal performance. This is
especially true in prestigious developments in city central locations, where rents and leases come at a premium.
Currently, manufacturers are prepared to invest in R & D to attract interest in their products for high profile commercial
projects, where they can prove their windows products and systems. As with all high-end production, technical
advances in window design will trickle down to the larger domestic market, both new and retro-fit installation.
Curtain Wall vs Window Wall
Traditionally, curtain and window walls were used for the different building types, but this has now become blurred as
high rise buildings become less sole purposed and more mixed use.
Curtain walling is a non-structural cladding to a building. Glazed curtain walls allow natural light to penetrate deep
into a building reducing operating costs as previously discussed. Traditionally used on commercial projects as the glazing
was outside the floor slab perimeter since office space is let on a m2 basis, this type of façade maximised the rentable
area. However, the non-domestic market has moved on and the demand for flexibility, better ventilation, aesthetics,
cost and speed of installation has made window walls a real design alternative.
Window walls these are individual factory glazed window and door units that fit between the individual floor slabs of
multi-storey buildings. Traditionally they were used in residential buildings, where property was sold or let by the
individual unit rather than by the m2.
The cost savings inherent in the design of window walls makes them attractive to developers, when comparing the
material, labour and installation costs against curtain walling. Costs associated with installing fire-breaks at the slab level
for curtain walling are removed totally from the project costs.
The project timeline can also be reduced, as floors can be completed and made wind and weather tight by installing
window walls as work progresses, allowing internal work to start earlier on the critical path. This is not feasible with
curtain walling.
Perhaps most important of all, quality of the finished product is enhanced because the glazed units are manufactured
off-site in a controlled environment. This reduces performance gaps by eliminating variability in the finished units. This
consistent level of quality means that curtain walls offer high thermal performance and provide very effective levels of
air tightness. This is helped by window walls being a systems application of previously engineered, tested and certified
fenestration products e.g. frames, glazed units etc.
Doors
External doors have one main function they are the opening in which users access a building. The external door forms
part of the building envelope, and is similar to windows in the way in which heat is lost through them. However, in
Ireland, the main method of heat loss through an external door is every time the door is opened.
Therefore, similar to windows, it is critical to ensure that U-values are low, and that the thermal bridges are eliminated.
US Dept. Of Energy - Window Types
Energy Saving Trust - Energy Efficient Windows
Green Spec - Energy Efficient Windows
USA Efficient Windows Collaborative
US Dept. Of Energy - Doors
Super Homes Energy Efficient Windows
The British Fenestration Registration Company T
EN Standards 12207 - Windows & Doors
UK N
S
F
‘
E
E
W
Technical Toolkit
Roofs
2.2.3.6
New Build
Roofs




This section outlines the correct methods of installing insulation a roof construction. The roof is the final element of the
building envelope, closing the building off to the external environment.
As with domestic buildings, non-domestic buildings utilise two types of roof constructions:
 Pitched roof
 Flat roof
Pitched Roofs
Insulating a roof depends on whether you want to insulate between the rafters, if you want to treat the roof space as an
occupied space, or insulate between the joists, if the roof space is not being used.

Carbon Trust: How to Implement Roof Insulation
Building Regulations Part L1A
0.25W/m2k.
Buildings Other than Dwellings states that the maximum permitted U-value for a roof is
Thermal bridges at roof and external wall junctions should be eliminated by ensuring a continuous insulation layer, as
discussed in Section 2.2.2.3 Walls.
Flat Roofs
Depending on the location of the insulation layer, a designer can broadly specify three basic types of flat roof:



Cold roof where the insulation is below the structural decking. The void is ventilated;
Warm roof where the insulation is above the structural decking. The void is not ventilated;
Inverted roof where the insulation is above the waterproof layer;
The elimination of thermal bridging and the prevention of the movement of moisture into the roof structure are key to
maintaining the thermal and structural integrity of the roof.
As with intermediate flooring, commercial flat roof systems can utilise
i) Shallow metal deck sheeting
Fig.1 Shallow metal deck sheeting (Source: Sika)
ii) Pre-stressed concrete planks
iii) Concrete block and beam decking, to act as the structural component of the roof.

QuinnTherm
A new form of block and beam, uses EPS panels moulded around two integral steel beams. This system ensures the
insulation layer is continuous with no thermal bridging spots, or gaps for moisture to move into the roof structure
Fig.2 An isometric section through a Quad-Lock roof detail (Source: Quad-Lock)
Fig.3 Cross-section through a Quad-Lock roof panel (Source: Quad-Lock)
Cool Roofs
B
HVAC
This is especially true for no-domestic type buildings that have a large flat roof surface parallel to the sky an optimal
position for maximising unwanted solar gain.
Generally such roofs are covered with three types of finish:



Ethylene Proplene Diene Monomer (EPDM) a synthetic rubber with glued or taped seams;
Thermoplastic Polyolefin (TPO) thermoplastic material with heat welded seams;
Chlorosulfonated Polyethylene (CSPE) a polymer material with heat welded seams;
It is when these types of roof finishes start failing, and building owners or occupiers investigate the reasons for that
failure, the issues around unwanted solar gain begin to be recognised. The heat build-up is not only causing internal
problems in the building, but has help accelerate the failure of the roof membrane.
Cool roofs use high solar reflective and low thermal emissive material to offset solar energy and to limit the amount of
radiant heat emitted from the roofing material.
The main benefit to building occupiers is the reduced operating costs associated with the cooling component of the
HVAC system. With a reduced heat load to manage, the HVAC
beyond its design capacity. Practically all HVAC system designs ignore the level of solar gain obtained through the roofs
of non-domestic buildings. Because usable space does not go up to roof level, the space immediately below the roof
often covers a service area or other non-specific space, where the superior insulation levels necessary to counter-act
any solar gain are generally not present.
Savings made on HVAC operating costs are increased by the need to use the HVAC less during peak times e.g. a hot
weekday, when there will be a peak in power demand as business and homes utilise their HVAC and SC systems, on top
of the existing demand from lighting, plant and equipment. A cool roof will help manage the buildings peak electrical
demand. Since commercial and industrial customers often pay a premium for additional power use during periods of
peak power, a cooler roof means less energy is required for the HVAC system.
It must be noted that cool roofing and roofing insulation are separate and different options for energy saving, and
should not be confused. The choice of which option to take is dependent on a number of factors such as climate, energy
prices and building use. The following points might be considered by those responsible for a buildings energy costs:
Add insulation to the roof or ceiling space if:
 There is less insulation than required under current local or national regulations;
 The building is in a climate with significant cold weather and heating needs;
 The roof exceeds 25% of the total building envelop (roof and walls);
 The cost of heating the building in winter exceeds the cost of cooling the building in summer
Apply a cool roof if:
 The building is in a location with a hot sunny climate for at least 3 months of the year;
 The HVAC duct system is in the roof/attic space;
 There are problems maintaining comfortable indoor conditions during the summer months the HVAC system
cannot cope with the cooling demand
 The roof exceeds 25% of the total building envelop (roof and walls);
 The cost of cooling the building in summer exceeds the cost of heating the building in summer
Carbon Trust -How To Implement Roof Insulation
Energy Saving Trust - Roof And Loft Insulation
Technical Toolkit
Ventilation
2.2.4.1
New Build
Ventilation
NZEB Air Tightness (RND)




Design air tightness into the project drawings and specification
Consider which type of HVAC system to design
Before designing the HVAC and heat recovery, consider
o Use of the building
o Local climate
o Thermal loading
o Humidity requirements
o Projected running costs
Comply with EN13779 in relation to:
o Outdoor air quality
o Supply air quality
o Indoor air quality
o CO2 levels
o Heat recovery requirements
o Indoor air humidity
Ventilation can be defined as the intended or unintended passage of air through a building, removing stale air and
replacing it with fresh air from outside.
It should be noted that ventilation may not be by choice it could be from draughts around external doors, windows or
open fire places. This will occur where a building is not airtight and has air infiltration and/or air exfiltration depending
on the local environmental factors. A lot of heat energy is lost through such ventilation, especially when there is a
significant difference between the inside and outside temperatures.
Regardless of whether air entering a building is controlled or not, it should be recognised that the air may not be fresh,
depending on the location of the building; for example a rural location compared to a city centre location. In a rural
setting, the air may be heavy with pollen or chemical sprays from nearby farms (depending on the time of year), whilst
in a city centre location, the quality of the air being brought in could be poor and loaded with pollutants and
particulates all year round.
Other factors associated with the decline of indoor air quality are the increased statutory requirements for energy
conservation and the steadily increase in utility bills. Both these have led to more air-tight buildings with historically low
levels of air exchanges.
Building Regulations provide guidance to architects and designers on the minimum ventilation standards required in
various buildings, and will often stipulate different requirements for different room types within the same building.
Please see Building Regulations Approved Document F1 Means of Ventilation.
Why Is Ventilation Required?
There are a number of factors why ventilation in a building is required, including:
1. Improve internal air quality:
 Remove pollutants such as CO2 VOC
 Remove allergens such as pollen and dust mites
 Remove odours and strong smells
2. Provide internal thermal comfort to occupants:
 Eliminate moisture from breathing, washing and cooking and the combustion of certain fossil fuels, and
preventing mould growth
 Minimise excessive heat during the warmer summer months
Low energy buildings will have a high degree of air-tightness, this means there is no unintentional ventilation through
draughty windows or chimney flues, which means stale CO2 and moisture laden air is not regularly exchanged, with the
internal space quickly becoming uncomfortable.
Building Regulations tend to stipulate the air-tightness level at which mechanical ventilation becomes mandatory. Care
must be taken to ensure and get a balance between providing a suitable level of ventilation and preventing heat energy
loss through excess ventilation.
Energy Performance Building Directive (EPBD)
Most of the changes to improve the levels of air tightness and ventilation in non-domestic buildings can be attributed to
Member States complying with the requirements of the (EPBD).
With thermal insulation levels and airtightness at such efficient levels, there are only two ways for HVAC designers to
further reduce energy demand:
i)
ii)
Lower the ventilation rate
Recover energy form the ventilation system
Given the current low rates of ventilation and the variety of non-domestic buildings, it is highly unlikely to be able to
reduce ventilation rates even further, maintain an acceptable level of air quality and further reduce energy demand.
It is reasonable to assume that in the remaining period to 2020, advances in HVAC technology to recover heat will
provide the most productive area of research to reduce energy demand.
In the context of an nZEB non-domestic building, can heat recovery be considered an acceptable answer? Passive
strategies are used when designing an nZEB non-domestic building e.g. orientation, high levels of insulation, airtightness, solar gain, renewable energy sources etc . But passive ventilation i.e. opening a window would allow heat to
escape and negate those passive design strategies. The question is - does heat recovery reduce energy demand or when
used for ventilation, is it a renewable source?
The answer lies in where the energy balance boundary is considered to lie:
a) Ventilated exhaust air becomes external air when expelled to the outside. By using the exhaust air as a heat
source before it is expelled, to warm the cooler incoming external air, this can be considered to be more energy
efficient than porting cooler external air direct into the internal environment, where it will require heating up;
b) A significant portion of the internal heat comes from renewable sources:
a. Passive design strategies such as solar gain (100% renewable);
b. Building occupiers (100% renewable)
c. The renewable portion of the buildings electrical demand (variable)
d. The renewable portion of the buildings heating demand (variable)
A significant proportion of any lost heat therefore comes from renewable sources, with the remainder almost
completely recycled through heat recovery which makes that heat energy available once again to the building. This cycle
is repeated a number of times, ensuring the most efficient extraction and recycling of heat energy.
Heat recovery can therefore be said to be a renewable energy source and fits within the nZEB ethos.
However with non-domestic buildings, heat recovery and HVAC system design will be depend on the use of the building,
local climate, thermal loading and humidity requirements of the building occupants. It may be necessary to project and
forecast the annual usage of the system and use these figures to derive a cost-optimal solution.
Such projections and forecasts must include the summer months if the HVAC is to be used to cool a building. An
efficiently designed system will reduce chiller energy loads. This may only be applicable where the building is located in
a Mediterranean type climate and experiences hot weather for three or more months of the year.
Similarly, it is possible to introduce an indirect humidification system into the exhaust stream. This can be carried out
two ways:

Indirect evaporative cooling with exhaust air
to the warmer supply air;

Indirect evaporation cooling with outside air
the supply or recirculated air;
EN13779 - European Standard for Ventilation and Air Conditioning in Non-Residential Buildings
Is a new standard for ventilation and room conditioning systems in non-residential buildings, EN13779 is now a legally
accepted standard in all member states of the European Union. The standard sets out to achieve a comfortable and
healthy indoor air quality (IAQ) in all seasons of the year at acceptable installation and operating costs, taking into
consideration the outdoor air. It represents a major step forward, recognizing the importance of external air in
achieving better indoor air quality and/or a healthier environment.
The standard provides designers guidance on system design and application:
 Aspects important to achieve and maintain a good energy performance in the system without any negative
impact on the quality of the internal environment;
 Relevant parameters of the indoor environment;
 Definitions of data design assumptions and performances;
Some of the key areas covered include:
System Requirements systems shall conform to national regulations and typically include:
 Location of air intake and discharge openings
 Air filtering
 Heat recovery
 Re-use of extract air
 Thermal insulation of the system
 Air-tightness of the system
 Pressure conditions within the system and buildings
 Power consumption
 Space requirements for components
 Aspects associated with installation, operation and maintenance.
Outdoor Air consideration to be given to the quality of the outdoor air around the building or its proposed location.
Where there is poor outdoor air, the designer must mitigate by:
 Locate air intakes where the outdoor air is least polluted OR;
 Apply a form of air scrubbing
Outdoor air is classified in Table 4 Classification of Outdoor Air (ODA)
Category
ODA1
ODA2
ODA3
Description
Pure air which may be only temporarily dusty (eg pollen)
Outdoor air with high concentrations of particulate matter and or gaseous pollutants
Outdoor air with very high concentrations of gaseous pollutants and/or particulates
Supply Air the quality of the supply air for buildings subject to human occupancy shall be such that, taking into
account the expected emissions from indoor sources and the ventilation system itself, proper indoor air quality will be
achieved.
Indoor Air is classified in Table 5 Basic classification of indoor air quality (IDA)
Category
IDA1
IDA2
IDA3
IDA4
Description
High indoor air quality
Medium indoor air quality
Moderate indoor air quality
Low indoor air quality
These classifications apply to air in occupied zones of the building.
Classification by CO2 level indoor air can be categorised by CO2
human bioeffluents. Classification by CO2 level is well established for occupied rooms where smoking is prohibited and
pollution is caused by human metabolism.
Category
IDA1
IDA2
IDA3
IDA4
CO2 level above level of outdoor air in ppm
Typical range
Default range
< 400
350
400 600
500
600 1,000
800
> 1,000
1,200
System tasks and basic system types ventilation, air conditioning and room-conditioning syatems are intended to
control the indoor air quality and the thermal and humidity conditions in the room to a specification agreed in advance.
The basic categories of the system types are dependent on its capabilities to control the indoor air quality and the
means and degree of control of the thermodynamic properties of the room. The category and type of control and
parameters to be controlled shall be specified.
Table 6 Possible types of control of the indoor air quality (IDA-C)
Category
IDA C1
IDA C2
IDA C3
IDA - C4
IDA C5
IDA C6
Description
The system runs constantly
Manual control. The system runs to a manually controlled switch
Time control. The system runs to a give schedule
Occupancy control. The system runs on motion detection eg infrared detectors
Demand control. The system runs dependent on the number of people present
Demand control. The system is controlled by sensors measuring CO2 or other gas,
as defined by the activity in the space.
Specific fan power the specific fan power shall be specified, with reference to national minimum requirements.
Heat recovery wherever heating or cooling of the supply air is required, the installation of a heat recovery system is
preferred. The energy impact shall be determined.
Thermal environment shall consider air temperature, operative temperature, air velocities and draught rate.
Indoor air quality shall consider supply flow air rates, the type of human occupancy, other known emissions, the
heating and cooling load and the extract airflow rates.
Indoor air humidity unless alternative information is available, the system shall be designed on the assumption that no
sources of humidity other than human occupancy and supply and infiltration air exist. Consideration shall be given to
condensation risks, winter/summer climatic conditions and energy issues.
Centralised or Decentralised HVAC
A designer of a non-domestic dwelling must weigh the advantages and disadvantages of whether to provide a central
located and controlled HVAC or whether to provide such a system on each floor of the building.
The costs of the installation will depend primarily on a number of factors:
 The number of floors upto approximately 10 storeys, a centralise HVAC system is more cost effective due to
base costs of key plant and equipment. Buildings with approximately 11 or more storeys, the reverse is true, as
M&E costs become lower;
 Typical floor area the cost of a decentralised HVAC located on each floor of a building, decreases as the size of
the floor increase to an optimal range of approximately 1,400m2 to 2,350m2. Above this size and there tends to
be a lack of space for service ducts in the ceiling or floor voids. Below this this size and the costs are higher than
a centralised system. This is also somewhat true for centralise HVAC with costs falling as floor size increases the
optimal range, but there is no significant drop in costs when floors reach this range;
 Space for ceiling ducts the cost and time of installing many kilometres of ducting for a decentralise floor-byfloor HVAC system far outweighs the ease and low cost of installing a central air supply and extract riser;
 Local fire regulations where mechanical smoke extraction is required, a centralised HVAC system is usually a
more cost effective option;




Architectural impact a floor by floor HVAC system reduces the impact on the architecture of a building
compared to a centralised system;
Energy costs in real terms no significant difference in running costs;
System controls controls for centralised HVAC systems have now caught up with the more localised control
afforded to a floor-by-floor systems, so unoccupied areas can now be deactivated. Whilst a decentralised HVAC
system offers the facility for local control, a properly designed centralised system with suitable controls should
be able to offer a similar service;
Maintenance this is really an area for risk analysis and reflection on previous experience. A failure in a
centralised HVAC system will disrupt all floors in a building. A failure in of a decentralised HVAC system will only
inconvenience those on that particular floor. The likelihood of a component failure on a centralised system is
lower than that of a decentralised system, despite the consequences of such a failure being more severe;
The decision on whether to use a decentralised floor-by-floor HVAC has been further complicated by developments in
integrating the ventilation system within the external envelope of non-domestic buildings. This allows designers to
provide individual ventilation to offices rather than provide general ventilation to an entire floor.
Advantages of individual HVAC:
 Energy saving demand orientated control, devices only running in occupied rooms and offices;
 Less space and floor area required, no need for supply shafts or fire dampers for ventilation ducts;
 Precise cost based consumption possible for each room and office;
 Individual room and office controls for ventilation and temperature;
 Increased building user satisfaction;
Disadvantages of individual HVAC:
 Excessive air flow problems due to noise and draughts;
 Air humidification and dehumidification is complex;
 Maintenance of multiple units requires more time;
 Multiple units makes heat recovery more complex could centralise exhaust air treatment?
 Higher energy consumption with open-plan offices;
 Wind pressure and outdoor temperature at the building envelope influence functionality;
Green Extension Architects - Low Energy House Ventilation
Low Energy Home - Information On Ventilation And Heating In Low Energy Homes
Good Homes Alliance - Ventilation And Good Indoor Air Quality In Low Energy Homes
Isover - Information On Energy Efficient Design, Including Air-tightness And Ventilation
Carbon Trust Heating Ventilation And Air Conditioning
The Residential Ventilation Association (RVA)
Breathing Buildings Low Energy Natural Ventilation
Technical Toolkit
Air Infiltration
2.2.4.2
New Build
Air Infiltration
NZEB Air Tightness (NBND)




o Local climate
o Thermal loading
o CO2 levels
Air infiltration can be defined as the unintended flow of external air into a building through gaps, cracks or other fissures
in the building fabric.
However, another source of air leakage is air exfiltration which can be defined as the unintended flow of internal air
from a building to the outside.
It should be noted that during periods of indoor heating, air tends to infiltrate through low-level gaps in the building
envelope and exfiltrate through high-level gaps in the building envelope. The reverse is true during periods of indoor
cooling.
Both of these sources of air leakage reflect the degree to which a building has been constructed or retro-fitted in an airtight manner and will affect the energy efficiency of the building.
So how does air leakage occur? genera
HVAC
other mechanic ventilation units. Where a building is not air tight, the degree of air leakage will depend on:
 The buildings age;
 The buildings form of construction;
 Its immediate surroundings;
 Regional or local climatic factors;
What is Air-tightness?
Air-tightness is
building fabric. It is not a measure of the extent to which a building is insulated. A well-insulated building is not by
default airtight; air can pass through mineral wool insulation. Similarly, an airtight building is not by default wellinsulated; foil or other impermeable sheeting can prove Air-tightness but not insulation.
Lack of air-tightness will lead to heat loss in a building as warm air is replaced by cold external air. Poor design, poor
construction techniques and environmental factors such as wind speed and direction can all influence the degree of air
leakage.
Air-tightness is checked using a Blower-Door Test.
The formula to measure air-tightness is:
m³ / h.m² @ 50Pa
Where:
m³ is the volume of air leaking from a building per hour
m² is the internal floor area of the building
50Pa is the differential pressure between the inside and outside of the building
The lower a reading the more airtight the building, for example a Passivhaus requires an air-tightness reading of
1m3/(hr.m2) @ 50Pa or less.
Why Is Air-tightness Needed?
A highly insulated non-domestic building with poor levels of air-tightness will not perform as designed and intended.
The building users will not experience optimum levels of thermal comfort, whilst the building owners will have
unexpectedly higher energy bills.
Poor airtightness is not only a waste of energy up to 40% more energy is required to heat a
building than an
airtight building - but a potential source of interstitial condensation when warm moist air is drawn through the building
fabric. As the damp air moves through the building fabric, it cools down and the moisture condensates inside the
building structure.
Unmanaged air will have the following effects on the internal building environment:
 Places additional load on the HVAC system to condition air;
 The air is not filtered or de/humidified;
 Can bring moisture into the building and structure:
o Condensation within the internal space
o Interstitial condensation;
o Mould growth;
 Reduces the comfort of the internal space;
 Causes draughts;
 Carries in dirt and pollutants into the internal space;
 Requires additional resources for cleaning and maintenance;
 Increase the use of HVAC systems:
o Increasing energy costs;
o Reducing maintenance periods;
o Increasing maintenance costs;
The amount of primary energy used in homes is approximately 25-30% of all energy consumption, with 40% of all global
energy demand being used to heat and cool buildings. This is reflected in the amount of associated CO2 emissions,
which is approximately 25-30% of all emissions. A building suitably air tight, will reduce its energy usage and thus help
to lower CO2 emissions.
Compliance with Building Regulations most national and local building regulations will have a requirement regarding
energy efficiency which includes controlling limiting the air permeability of the building fabric.
How Is Air-tightness Achieved?
Non-domestic buildings present particular challenges to achieving air-tightness. Such buildings often have large
entrances, roller shutters, rapid rise doors, revolving doors, automatic sliding doors or other special form of opening.
Whilst is may be difficult to completely seal these doors, it is vital to minimise the leaks where possible by using:
 A strip that can be compressed between the component and the structure;
 A pre-compressed strip that expands to fill the gap between the component and the structure;
Larger non-domestic buildings will often include lift-shafts, plant/boiler rooms, basements areas, underground carparks,
warehousing and/or loading bay areas. If these are to remain unheated, they can be considered outside of the line of
the air barrier. However, adjoining floors/ceilings and walls must be treated as the line of the air barrier and made air
tight.
Sealing gaps is vital to provide an air tight envelope. Where possible use regular shaped ducts or cable trays, so its easier
to make and seal the opening.
Fig1. Air Tight Envelope (Source: GBG67 Part3)
Where similar openings have to be made throughout the building, it is easier if the openings are all the same size.
People will be more familiar with how to form and more importantly the correct method to use to provide an air-tight
seal:
 Check whether the opening requires fire protection
 Ensure there is sufficient space between any penetration and the opening so it can be sealed effectively;
 Gas and water pipes should be sleeved with an adjustable tightfitting collar;
 The gap between a pipe and sleeve should be sealed with a non-setting mastic at either end
Where irregular openings are formed e.g. cable trays, these will require a custom solution, generally an air impermeable
rigid material
Where sealing around electrical cables, especially larger incoming phase cables, it should be noted the potential hazard
caused by the applied insulation or sealant causing local overheating of the cable. Check with local regulations and fire
standards.
Recessed lighting presents problems with forming an air tight barrier in the ceiling void. It is vital to ensure the void
where the recessed light is seated, is sealed in the immediate vicinity.
Suitable materials for sealing openings include:
 Gun applied elastomeric sealants - Should be able to cope with movement and maintain adhesion to
surfaces;
 Site applied expanding foam normally expands up to 15 times its initial volume. Used for large gaps, but
may require elastomeric sealant around the edges;
 Gaskets for movement joints to seal around services;
Air Tightness by Design
An airtight building is achieved both by the design team and the trades on site engaging in
together.
and working
At the design stage, airtightness can only be achieved if the architect or building designer understand the following:
 The causes of air infiltration and air exfiltration, the building physics and the movement of moisture through a
structure. They can then design appropriate details to eliminate any air leakage
 The need to keep detailing simple so they can be constructed correctly
 The need for a continuous airtight barrier made easier to denote on drawings if the detailing is simpler
 The need to balance airtightness with ventilation and the need for thermal comfort for the building users and
designs appropriate ventilation systems. It should be noted that airtightness greater than 3m3/h.m2 at 50Pa will
require a mechanical system
 The need to provide drawing details for the site manager and trades to illustrate how penetration of the airtight
barrier will be sealed and with what material e.g. tape, gasket rings etc.
 The need to correctly specify materials and equipment required to achieve airtightness
On site, airtightness can only be achieved if trades are aware of:
 The importance of the airtight barrier
 Where the airtight barrier is to be located
 Work should be correctly scheduled to ensure (re)sealing is correctly carried out
 Trades to strictly follow the architects drawings, bring any anomalies to the attention of the site manager and
not to interpret or take shortcuts
 Trades to work as a team rather than a collection of individuals ie
Air Tightness Strategy
Air tightness on a building project will not just happen. To ensure that air tightness is achieved, it is necessary to
develop a strategy to deliver the desired objective. On larger non-domestic building projects such a strategy is vital,
owing to the general size and complexity of build. When developing such a strategy, the design team should consider
the following:
 Appointment of an independent air tightness advisor;
 Appointment of an air barrier manager on site;
 Identification of the air barrier at an early stage in the design process;
 Inform the design and project team of the vital importance of the air barrier;
 Air tightness and the air barrier to be included in all contracts;
 Specify air tight materials and components;
 Check interface between components to ensure they work together;
 Inform the site management team of the location and importance of the air barrier;
 Hold toolbox talks with operatives and trades carrying out air tightness critical work;
 Arrange regular checks of the air barrier for completeness whilst it is still visible and accessible;
 Schedule well in advance for a competent body to conduct air tightness testing include pre-testing site visit(s);
 Ensure the air tightness works are completed;
 Prepare building for air tightness testing;
 Conduct air tightness testing;
Blower Door Test
Carrying out a Blower-Door Test is a critical part of establishing whether a building has an appropriate degree of air
tightness. A building ready for testing, has all external windows and doors closed with a temporary fan and
impermeable membrane placed in one of the external door frames. The fan under or over pressurises the building, with
the volume of air leaking in or out of the building being measured. It is important to conduct tests using under-pressure
and over-pressure, because depending of the barometric circumstances; both are possible and can have different
results.
Fig2. Blower Door Test (Source: BMTRADA)
Typically a test will involve the following stages:





Measure the environmental conditions present at the time of the test (temperature, humidity, and barometric
pressure), so the results can be correct;
Identify the location of the fan unit;
Install the appropriate number of fans for the building size and target permeability;
Measure air flow at a number of pressure differentials;
Enter the data into software to generate a result;
Building Research Establishment - Links To Information On Air-tightness
Low Energy Homes - Air Leakage Test
US Dept. Of Energy - Air Leakage Guide
Chartered Institution Of Building Services Engineers (CIBSE) - CIBSE Guide A: Environmental Design
Passive Haus Institute - Information On Air-tightness
Technical Toolkit
Building Physics
2.2.4.3
New Build
Building Physics




o Local climate
o Thermal loading
o CO2 levels
Building Physics looks at how a building, its occupants, internal services, the internal and external environments co-exist
and interact with one another.
The science of Building Physics is used when designing new buildings to ensure the client and building users have an
energy efficient and comfortable living/working environment. The science can also be used to design retro-fit
programmes, to help identify and prioritise the most appropriate measures to give the best energy savings.
Fig1. Energy Loss (Source: The Royal Academy of Engineering)
Consideration of Building Physics will ensure greater usability and comfort for building users. Software is now often
used to provide energy modelling to ensure heating/cooling, ventilation/heat exchange, lighting etc. are optimised to
provide the most energy efficient design. The software will consider thermal and moisture variations, condensation
prediction, daylight and shading, microclimate and external airflow.
Why Is It Important?
With rising energy costs in the built environment usually associated with heating/cooling/lighting
demand for buildings to be energy efficient and environmental friendly as possible.
there is a growing
By maximising the Building Physics of a building, the following benefits can be obtained:
1. Better building design
2. High levels of building user satisfaction and comfort through optimising internal thermal, lighting, humidity
levels
3. Energy efficiency and reduced operational costs through energy efficient building design with resultant lower
energy bills
4. Reduce the consumption of fossil fuels and CO2 emissions
5. Reduced impact on the natural environment
6. Increase the level of sustainability of a building, both during construction and in when in use
The following list is not exhaustive, but gives an indication of some the factors to be considered. It should be noted that
when considering these factors for a
, care should be taken to consider each measure against the
design and construction of the original building.
Air-tightness and Ventilation aside from controlling the air-tightness of a building to limit heat loss, and the presence
of interstitial condensation, controlling the extent and amount of ventilation is also important, to ensure the correct
exchange of stale and fresh air, optimise levels of humidity and maximise the opportunity for heat recovery.
Fig2. Blower Door Test (Source: DB International)
Thermal comfort/performance the thermal performance of a building is a key aspect for building users wellbeing and
satisfaction with their home or work environment. Successfully controlling heating and cooling within a building and
controlling the heat loss or gain, through its structure, will have a profound impact on energy efficiency and associated
costs. Consideration must be given to the insulation provided to the building envelope, air-tightness and the type of
heating system to be used.
Fig3. Thermal Comfort (Source: Isover)
Moisture movement moisture enters buildings through a number of ways: i) gravity (leaks), ii) capillary action
(rainwater penetration), iii) air convection (condensation), iv) vapour diffusion (moisture moving through a building
material). It is important to eliminate these to prevent mould and damage to the building structure.
Fig4. Moisture Movement (Source: CZ ENergy)
Solar gain/loss the orientation of a building and the subsequent effect the sun will have on its occupants can be
profound. Too much solar gain, can make for an uncomfortable internal environment too hot and/or too much glare,
resulting in windows or air conditioning being used to cool down the environment (potential for poor air quality from air
borne pollutants and high energy costs). Poor building orientation and too little solar gain can increase the use of
artificial lighting and increase the demand for heating. Correctly designed buildings, will exploit the sun to maximise
natural lighting into the building and provide renewable space and water heating.
Fig5. Solar Gain (Source: WBDG)
Lighting incorporating natural daylight into the overall lighting design of a building can reduce the need for artificial
lighting. It is difficult to do, because natural lux levels vary, but its inclusion can affect such decisions as number of
sources, there location and intensity etc.
Fig6. Incorporating Natural Daylight (Source: Architects Journal Blog)
Emissions from building products whether designing a new building or undertaking a retro-fit project, it is important
to establish the nature of the building products specified, to eliminate or at least minimise the amount of volatile
VOC
VOS
Fig7. Volatile Organic Compounds (VOCs)(Source: Ecotextiles)
Acoustics when controlling noise in a building consideration must be given to impact and airborne (both external and
internal) noise sources. Building materials suitable for noise reduction, may not necessarily be suitable to moisture
movement through the structure, nor be the most appropriate in terms of thermal conductivity.
Fig8. Sources Of Noise (Source: URSA Urilata)
Climate this is really an overview of a number of factors that are local to a building i.e. temperature range, hours of
daylight, rainfall and relative humidity, wind speeds etc
Radon is a naturally occurring radioactive gas that can have a serious detrimental impact on indoor air quality, but can
be safely removed from the internal environment at home or work. Design of new buildings should automatically allow
for the installation of radon barriers. Retro-fit projects should allow for monitoring and adequate ventilation or air
exchange.
Fig9. How Radon Enters A Building (Source: Radon.ie)
International Building Physics Toolbox - Simulation Toolbox For Building Physics Elements
National Renewable Energy Laboratory - Information Including Computer Testing For Energy Audits
Fraunhofer Institute Of Building Physics
ARUP - Building Physics
Sheffield University Architectural Engineering Design - Building Physics
Technical Toolkit
Moisture Movement
2.2.4.4
New Build
Moisture Movement




o Local climate
o Thermal loading
o CO2 levels
Moisture movement in buildings takes many forms and plays a major contribution to the comfort of building users, the
quality of indoor air and the uninhibited growth of mould.
Moisture can enter a building in four basic ways:
1.
2.
3.
4.
As a vapour invisible to the eye through vapour diffusion, which can take place above and below ground
As small water droplets carried in the air
As large water droplets rainwater penetration
Through capillary action usually through contact with groundwater
The study of such movement is called psychrometrics and analyses the relationship between moisture content, air
temperature and humidity. Such relationships have been simplified into a usable format called a Psychrometric Chart.
The chart is used to indicate the dew point temperature by:
i) Calculate the relative humidity
ii) Identify the air temperature along the lower axis
iii) Move directly up until you cross a blue curved relative humidity line or interpolate as necessary
iv) At this intersection, move horizontally across to the left-hand axis this will give the dew point temperature
Fig.1 Psychrometric Chart (Source: Ohio University)
Dew Point this is a variable point within the building envelop and depends on a number of factors such as the U-value
of the various components of the wall and the relative humidity of the air, the internal and external air temperature,
vapour pressure etc. It is the point where interstitial condensation forms within the fabric of a building.
It is possible for there to be no dew-point within the building envelop if the level of heat loss is significant and outways
the difference in temperature between the internal and external readings. When people are aware of the level of heat
loss, they turn down their heating, this will lower the temperature gradient to a point where it crosses the dew-point
line (which remains the same), resulting in condensation being produced on the inside face of the plasterboard.
To improve the thermal properties of a wall, it is best to keep them dry and often and waterproof render or a
proprietary insulation system is applied to the external face. This creates a barrier for the moisture trapped in the wall,
and leads to the formation of an interstitial condensation near the external face, where the temperature crosses the
dew-point.
The alternative treatment of applying insulation to the internal face, also has potential problems. The insulation blocks
the movement of heat into the building envelop, lowering the temperature of the envelope to the point where it cross
the dew-point, and interstitial condensation forms just behind the insulation or just within the building fabric itself. This
is a particularly damaging form of interstitial condensation as it has the potential to cause significant damage to the
building structure.
Control Of Moisture Movement
There are a number of reasons to control the passage of moisture in a building and through the building fabric, such as:
Air Quality & Comfort low or high levels of moisture in the air can cause uncomfortable levels of relative humidity, and
make the occupation of a building a very unpleasant experience.
Low levels of relative humidity can result in building users feeling itchy and parched, as their skin and nasal membranes
dry out. Unfortunately, there tends not to be any agreement on what is considered an acceptable low level of relative
humidity and tends to split along medical or comfort perspectives.
High levels of relative humidity can result in building users feeling hot and sticky, whilst during the winter, building users
will feel cold. There is growing agreement that 70% is the upper limit of relative humidity within a building, and ideally
A
be injurious to health.
Condensation - Can arise when poor ventilation is combined with a suitable mix of air temperature and humidity.
Moisture is always present in the air from activities such as washing, cooking and breathing and unless suitable
ventilation and insulation is present will result in the formation of condensation.
There are three forms of condensation:
Interstitial condensation is caused when internal warm air which holds more moisture and has a higher vapour
pressure than external cold air, tries to escape from a building (exfiltration). If the building has poor air-tightness, the
internal air will pass through the building fabric (exfiltration) and at this point, it the air temperature drops to its dew
point, condensation will form inside the building envelope.
Warm-front condensation is common in the British Isles during the winter months of November through to February,
and occurs when a warm-front arrives from the Atlantic Ocean. It usually affects buildings with significant
masonry/concrete structures, where condensation runs down the cold internal walls, such as castles, or underground
structures such as car-parks.
Cold-bridging condensation is associated with poor insulation and is caused when heavily laden warm moist air comes
into contact with the building fabric, where the temperature of the structure is at or below the dew point of the air.
Such a situation is not uncommon in external walls along the skirting level, where it is often mistake for a failed damp
proof course, where the under-floor insulation has not being carried up to meet the cavity insulation.
How to control Moisture Movement
There are three main ways to control moisture movement within a building:
Manage the ventilation Whilst the design of HVAC systems is a sophisticated process, it is often difficult if not
impossible for system designers to make allowances for localised pressure differences that force humid air outwards
into colder cavities and voids with the building envelope. In theory it is possible for the HVAC system to be designed to
accommodate to the airflows leaving and entering a building, but in reality non-domestic buildings tend to be large
structures, with many internal spaces, some outside the air barrier, and partitions that imped the flow of air.
With HVAC calculations based around average pressure figures, this does not mean in reality that some parts of the
building will not experience a positive air pressure relative to cavities and voids in the building envelope ie forcing
moisture into the building envelop.
To prevent this from occurring, it is vital to ensure the building is made air tight with a good air barrier. This will prevent
moisture laden high-vapour-pressure air getting into the cold side of the building envelop and creating interstitial
condensation. Such an air/vapour barrier should be used in conjunction with a HVAC system, to ensure the building is
ventilated in a controlled manner.
Control the levels of heating heating should be low level background heating, which will increase the internal surface
temperature of the building envelope. This will be especially helpful in older more historic buildings of mass masonry
construction, which are prone to warm-front condensation and may not be suitable for the application of various
internal or external insulation systems.
Insulation the correct and proper application of a suitably selected and designed insulation system will improve the
temperature gradient of the building envelope, and move the dew-point to a position where any interstitial
condensation that does form will do so in a location where it can do no damage. The insulation design and application
needs to be sufficiently detailed to address any potential areas of thermal bridging thus eliminating the opportunity for
warm moist air to come into contact with cold surfaces to form condensation and possibly mould growth.
Alternatives to HVAC Dehumidification
There are four potential alternatives to the dehumidification units associated with HVAC systems, that have been
developed in recent years. Such development has been driven by the concern to provide a good standard of indoor air
quality to offset the increased levels of air tightness and reduction in air infiltration. These dehumidification alternatives
are energy efficient and affordable.
Desiccant system a desiccant wheel is used to remove moisture form the air. The dry air is then cooled and the
moisture removed from the wheel through heating, reactivating the desiccant for further dehumidification.
Enthalpy wheel similar to desiccant wheels but use less desiccant, spin much faster and use exhaust air rather than
heated air to reactive the desiccant. These wheels rely on a moisture differential between the supply and exhaust air to
work. The lower the differential the lower their performance.
Heat pipes use sealed tubes containing refrigerant that are added to AC units to increase their dehumidification
capability. The tubes passively remove heat from the incoming air and allowing the evaporator to extract more humidity
without an increase in energy usage.
Dual path system these tend to used in the retail sector. They are custom made with a long lead-time and are
expensive. The system separately dehumidifies and cools the outside air before mixing it with conditioned return air and
ducting it into the retail space.
Problems with Dry Air
Whilst it is important to manage the movement of moisture with a non-domestic building and the building envelope, it
should be remembered that dry air can cause problems for building users and in some instances can be a threat not
only to the building users but also to the building itself.
Safety
In an industrial setting where the building is used to process hydroscopic materials such as wood, paper, textile fibres,
leather or chemicals, dry air can cause damage to the products or affect the production process. In factories where the
production process creates significant amounts of dust and potentially explosive atmospheres, a build-up of static
electricity caused by dry air is extremely dangerous.
Humidity and Comfort
Research has shown that most people are happy with humidity levels of between 35% and 55%, this is in part due to
human perception for example a person will feel chilly when the room temperature is at 23oC if the air is dry. Since
human perception of relative humidity is experience as a temperature differential, it is possible to combine lower
internal room temperatures with the correct humidity levels and actually produce thermally comfortable working
conditions. Not only will the building users be happy, but so will the building owner with the energy savings and reduced
utility bills.
Electrical Equipment
It is possible for electrostatic discharge (ESD) to accumulate in dry air of an office environment, and can create voltage
spikes in the CPU of electrical equipment such as laptops and printers. ESD may contain a higher voltage than a lightning
strike. It is also possible for a person to accumulate static electricity, which is discharged when they approach a door
handle
Issues to be considered
At the design stage, the following should be identified and appropriate specifications drawn up to prevent unwanted
moisture entering the building envelop:
 Consider the local climate the location of the project will be a major influence on the measures taken eg a
coastal location will be far more humid than a site 100km inland. The placing of the air/vapour barrier will be
dependent on whether the climate is warm or cool to the outside of the building envelope in warmer climates
and towards the inside in cooler climates;




Select appropriate materials make sure the materials can actually do the intended function eg do not specify
an air barrier when a vapour barrier is required;
Correctly design and size the HVAC system oversized systems will release too much cool air too quickly, whilst
undersized systems will not be able to cope with the heating or cooling demand;
Detail fully insulation to HVAC pipes and ducting to prevent condensation from forming and dripping into the
building fabric;
Review the specification for potential issues in a holistic manner so it is easier to see how changes to one part
of the specification may have potential consequences for another part eg: changes to the building design may
require an update to the HVAC system or new details for the air barrier;
The common modes of moisture entering a building, where the resultant damage may be caused, the prevailing
weather and the path of access.
Moisture
Movement
Air leakage
Vapour
diffusion
Capillary action
Gravity
Occurrence
Location
Usually at or near
the top of a
building
Anywhere in the
building envelop
Usually at or near
the bottom of a
building
Water source
above affected
area
Prevailing wind
Generally
discrete
Weather
Conditions
Mid-winter and
spring thaw
Widespread
Spring thaw
Widespread
Whenever water
temperature is
above freezing
Whenever water
temperature is
above freezing
After heavy driving
rain
Discrete
Path of Access
Requires air leakage
pathways in
building envelope
No obvious faults
may be visible
Occurs through
porous material
Requires leakage
paths below water
source
Wind-driven
Generally
Requires water
rain
widespread
leakage pathways in
building envelop
Surface
On any cold
Generally
During coldest part Condensation may
condensation
surface
discrete
of the year
be absorbed into
porous surfaces
Fig7. Common Modes Of Moisture Entering A Building (Source: Oak Ridge National Laboratory)
The table below shows the difference between vapour diffusion and moisture movement:
Moisture Movement by Vapour Diffusion
Does not require an air pressure difference
only requires a vapour pressure or temperature
difference.
May be in the opposite direction than air
movement eg: in an air conditioned building
during the summer in a humid climate, air moves
from the inside to the outside. However,
because of the high humidity and high external
temperature, vapour diffusion will occur from
the outside into the building.
Reduced by properties of vapour barrier not as
dependant on tight seals and joints.
Moisture Movement by Air
Moves through building envelop because of
an air pressure differential.
May be in the opposite direction to vapour
diffusion. Moves through building envelop in
direction of air pressure differential.
Reduced by sealing the building envelop in a
continuous blanket very dependent on tight
seals and joints.
Affected by permeability of the material.
Affected by wind, stack and mechanical
systems and the air barrier properties of the
system.
More
forgiving
during
retrofitting
/
Easy to lose continuity during retrofitting /
refurbishment projects.
refurbishment projects, thereby reducing the
effectiveness of the air barrier properties.
Moves small volumes of moisture (10-30% of
Moves large volumes of moisture (70-90% of
total quantity).
total quality).
Fig8. Difference Between Vapour Diffusion And Moisture Movement (Source: WR Meadows)
National Institute Of Building Sciences - Whole Building Design Guide - Mould & Moisture Dynamics
WR Meadows - Controlling Moisture Movement In Buildings
RCI Institute Of Building Envelope Consultants The Great Moisture Movement
Oak Ridge National Laboratory - Case Studies Of Moisture Problems In Buildings
Dew Point Calculator
Texas Bureau Lathing & Plastering - How To Avoid Moisture Damage To Walls From Condensation
Building Conservation
Building Science - Relative Humidity
Northern Arizona University - Thermal Comfort (Relative Humidity & Air Temperature)
Level (The Authority On Sustainable Building)
Insulation Express - Interstitial Condensation, Breathability & Solid Wall Insulation
Cement Concrete & Aggregate Australia - Condensation Design Strategies
Dwellings - New Build
Technical Toolkit
Heating And Hot Water
2.2.5
New Build
Heating And Hot Water
NZEB Heating and Hot Water




Utilise high efficiency systems for thermal energy requirement:
o Use highly efficient boilers or heating systems
o Size the heating system accurately
o Service the heating system appropriately to maintain its efficiency
Utilise effective heating control
o Programmable 7 day time, temperature and zone control
o Prevent boiler from coming on when not needed (interlock)
o Ensure the controls designed and installed are usable by the occupant
Consider renewable energy heating and hot water
o Solar hot water
o Heat pumps
o Biomass
Maximum permitted electrical & heating primary energy demand is 35 to
285kWh/m2/yr depending on the type of reference building
The amount of energy used for heating of spaces and hot water in a non-domestic building varies largely depending on
the use of the building. Chartered Institution of Building Services Engineers (CIBSE) Guide B: Heating, Ventilation, Air
Conditioning and Refrigeration, as well as CIBSE Guide A: Environmental Design and CIBSE Guide F: Energy Efficient
Building Design, outlines the correct design approach required for the correct sizing of heating systems in buildings.
Building Regulations approved document L outlines that in order to ensure compliance with the building regulations,
the amount of energy used for heating a property will be limited by:
 Reducing heat loss
 Maximising solar gains
Dwellings - New Build



Commissioning of energy efficient space and water heating systems
Use of effective controls
Boilers must have high efficiency
This section outlines in detail some of the key aspects in terms of reducing energy consumption due to heating and hot
water, to ensure that above standards are met.
Carbon Trust Energy Efficient Heating
Heating And Hot Water Industry Council (HHIC)
Non Domectic Buildings New Build
Technical Toolkit
Boiler Types
2.2.5.1
New Build
Boiler Types




o Solar hot water
o Heat pumps
o Biomass
Choosing the right boiler for a building and making sure that it is as efficient as possible will ensure that it will provide
heat and hot water as efficiently as possible.
A boiler is used to heat a heat transfer medium, typically water, which is pumped around the building to supply heat to
radiators and hot water tanks. In Europe hydronic (hot water) systems are most common, but in other parts of the
world air is directly heated by the burning fuel in a furnace and this is pumped around the building in large ducts. For
most buildings one boiler is sufficient to supply hot water at fast enough a rate to heat up all the radiators to their
design temperature and to also heat up the water in the hot water tank.
Boilers have a common basic design; fuel with some calorific value is burnt in air by a burner section of the boiler, the
hot vapour generated is used to heat water flowing through pipes or in a jacket around the fire box.
In addition to the basic principle behind boilers there are many design and control innovations that can be applied to
There are many different types of boilers, depending on fuel type and output. The main ones are:

Combination boilers - combination boilers heat hot water on demand and are widely used. They are not
quite as energy efficient as a regular or system condensing boilers but there is no heat loss from a hot
water tank so are useful it there is a low hot water demand.
Fig1. Combination Boiler (Source: MK Heating Engineers)

Regular Boiler A regular boiler is also known as a traditional or conventional boiler and consists of
separate controls, cistern and a hot water tank.
Fig2. Regular Boiler (Source: MK Heating Engineers)

System Boiler a system boiler is similar to a regular boiler but with an important difference, the boiler
contains an expansion vessel which means the feed and expansion tank is not required in the loft, saving
space. There are two types of system boilers:
-
Vented cylinder -with a vented hot water cylinder, the cylinder is fed by a cold water
storage tank in the loft. The pressure that forces the water out of the taps is generated
by gravity, which suits a property with low mains pressure
Fig3. System Boiler with Vented Cylinder (Source: MK Heating Engineers)
-
Unvented cylinder -unvented cylinders, suit properties with good water pressure, as they
get their water directly from the mains. This means that the hot water system operates
at mains pressure, making it possible to have power showers without the need for a
pump
Fig4. System Boiler with Unvented Cylinder (Source: MK Heating Engineers)

Back Boilers - back boilers combine a fireplace with the boiler located behind it for central heating and hot
water.
Condensing and non condensing
There are condensing and non condensing versions of the above boiler types. Condensing boilers are high efficiency
boilers (typically greater than 90%) as the waste heat in the flue gases are used to pre-heat the cold water entering the
boiler. Non condensing boilers do not have an extra heat exchanger to make use of the waste gases, so the hot gases
are expeled outside through the flue. A non-condensing boiler will typically take air in from inside the room, whereas a
condensing boiler will be fully sealed and takes air in directly from the outside.
Fig5. Condensing Boiler (Source: Micro Greening)
Fig6. Non Condensing Boiler (Source: Micro Greening)
Design considerations
T
either as a new build are:
1. Size the boiler accurately for the actual heat load of the building. This will ensure it works at its maximum
efficiency. It is common practice for plumbers to oversize boilers. This results in boilers that are too powerful for
the building and they have to cycle on and off frequently
2. C
T
little fuel the boiler wastes. It is possible to get boilers around 97% to 98% efficient
3. Ensure that the boiler chosen is suited to the plumbing system. If a boiler is a condensing boiler it is important
to run it at a slightly lower temperature to ensure it operates in condensing mode, this can be achieved by
having slightly larger radiators or timing the heating to allow slightly longer for the system to come up to
comfortable heat levels
4. E
possible
Biomass
A biomass boiler can be used in place of a standard gas or oil boilers to heat radiators for a whole building and to
provide the hot water. Stoves can also be used in conjunction with a back boiler to heat radiators and provide hot
water. There a three types of biomass that can be used:



Wood Pellet wood pellet boilers can be sourced at small output sizes to suit a low heat load building. wood
pellet boilers are fully automatic if installed with a fuel hopper for bulk deliveries similar to oil or LPG deliveries.
Heating with biomass is a renewable form of heating and is carbon neutral.
Wood Chip wood chip boilers are is similar to wood pellet but the fuel is less possessed and is suited to larger
boilers.
Wood Log wood log boilers are not automatic, the user must load the log box every day or two. The big
advantage is that the fuel can be grown by the owner or sourced locally.
Combined Heat and Power (CHP):
Combined heat and power (CHP), also known as co-generation, is the simultaneous production of heat and electricity
from a single fuel source such as natural gas, biomass, biogas, coal or oil. The system generates electricity, capturing the
normally wasted heat produced during this process, and uses it as space and hot water heating source. CHP is covered
in more detail in the Electricity section 2.1.20.3 CHP. Please refer to this section for more information.
Energy Savings Trust - Boiler Types
Sedbuck - Boiler Efficiency Information
Energy Savings Trust - In-situ Monitoring of Efficiencies of Condensing Boilers and use of Secondary Heating Trial - Final
Report (2009)
Planning Portal Boilers and Heating
Carbon Trust - Steam and High Temperature Hot Water Boilers
Carbon Trust Low Temperature Hot Water Boilers
Carbon Trust Biomass Heating Users Guide
Biomass Energy Centre
IEE Forest Project
CONCERTO
Heating and Hot Water industry Council (HHIC)
Technical Toolkit
Ground Source
Heat Pump
2.2.5.2
New Build
Ground Source Heat Pump




o Solar hot water
o Heat pumps
o Biomass
Ground source heat pumps operate by taking low grade heat from the ground and water near the building and
upgrading this heat by means of an electrically powered compressor. The technology offers high efficiencies, which are
quoted as Coefficient of Performance (COP); the COP is the ratio of energy supplied by the system divided by the
electrical energy consumed by the system.
Fig1. Ground Source Heat Pump Systems (Source: rays-hvac.com)
Ground Source Heat Pumps typically have a seasonal performance factor of circa 4.4. It is very important that heat
pump systems are coupled with suitable low heat distribution systems such as fan coils, low temperature radiators or
underfloor heating. This is because the quoted seasonal performance factors are normally for low temperature systems.
Ground source heat pumps require pipe work to be laid externally to absorb heat from the ground, this can be either a
looped horizontal circuit of pipe-work buried at about 1.5m to 2m depth (for approximately one to two times the area
of the building) or it could be installed in a vertically (including radial; diagonal bore-holes drill at 30 60 degrees from a
single manifold) drilled well. The latter requiring a specialist drilling rig. This option has a higher cost but much lower
space requirements
Fig2. Radial Drilling Ground Source Heat Pump (Source: ESP Energy)
Design Considerations



It may be advisable to install a heat pump with a thermal store to enable the system to be run at night using
lower cost off peak electricity and to meet some peak loads
Heat pumps require modern low temperature radiators or underfloor heating, which will allow the heat pump
to operate at a low output temperature
The heat pump should be sized completely differently to oil or gas boilers. They must be sized to run at full
capacity for most of the year, which means they should not be sized to meet the maximum heat load of the
building, for the coldest day of the year. A second system such as a peak boiler or a stove should be used for the
couple of days per annum when this is required.
Benefits




The main benefit of ground source heat pumps is that for every unit of electricity used to power the compressor
3.5 to 5 (or possibly more) units of heat are delivered to the building
Ground source heat pumps operate at a higher seasonal COP than air source heat pumps because they are using
the ground as their heat source, which does not vary much in temperature all year round
A heat pump does not require much interaction from the building occupant other than that they are serviced as
As the national electricity supply becomes greener with the addition of more wind turbines and high efficiency
gas generation technologies such as heat pumps associated emissions are dropping
Energy Savings Trust - A Buyers Guide to Heat Pumps
Heat Pump Association
Ground Source Heat Pump Association
Microgeneration Certification Scheme
Energy Saving Trust Heat Pump Trials
Carbon Trust - Ground Source Heat Pumps
Technical Toolkit
Air Source Heat Pump
2.2.5.3
New Build
Air Source Heat Pump




o Solar hot water
o Heat pumps
o Biomass
Air Source heat pumps operate by taking low grade heat from the air outside building and upgrading this heat by means
of an electrically powered compressor. The technology offers high efficiencies, which are quoted as Coefficient of
Performance (COP), the COP is the ratio of energy supplied by the system divided by the electrical energy consumed by
the system.
Unlike ground source heat pumps air source does not require expensive and or space consuming heat exchange loops
underground as they use air as their heat source.
Design Considerations





Unlike ground source heat pumps air source does not require expensive and or space consuming heat exchange
loops underground as they use air as their heat source
It may be advisable to install a heat pump with a thermal store to enable the system to be run at night using
lower cost off peak electricity and to meet some peak loads
Heat pumps require modern low temperature radiators or underfloor heating, which will allow the heat pump
to operate at a low output temperature
The heat pump should be sized completely differently to oil or gas boilers. They must be sized to run at full
capacity for most of the heating season, which means they should not be sized to meet the maximum heat load
of the building, for the coldest day of the year. A second system such as a peak fossil fuel boiler or a stove
should be used for the couple of days per annum when this is required
Air source heat pumps are best suited to well insulated building and not suited to poorly insulated and draughty
buildings
Benefits





The main benefit of air source heat pumps is that for every unit of electricity used to power the compressor 3 to
4 units of heat are delivered to the building
Air source heat pumps are cheaper to install and can be fitted without digging up a large area for the heat
exchanger pipe loops, or drilling bore holes
A heat pump does not require much interaction from the building occupant other than that they are serviced as
As the national electricity supply becomes greener with the addition of more wind turbines and high efficiency
gas generation technologies such as heat pumps associated emissions are dropping
In very large buildings where heating and cooling may be required in different areas at the same time, an air
source heat pump is a very effective solution as some models are available that can use excess heat in one
location to provide cooling to another
Fig3. Simultaneous Cooling and Heating (Source: johnsoncontrols)
Drawbacks

Geothermal heat pumps operate at a higher seasonal COP than air source heat pumps because they are using
the ground as their heat source, which does not vary much in temperature all year round. In other words, air
source heat pumps are less efficient when the outdoor air temperature is very low. This is why it is very
important to compare SPF not COP.
Energy Savings Trust - A Buyers Guide to Heat Pumps
Heat Pump Association
Energy Saving Trust Heat Pump Trials
Carbon Trust - Ground Source Heat Pumps
Technical Toolkit
Heat Recovery
2.2.5.4
New Build
Heat Recovery




o Solar hot water
o Heat pumps
o Biomass
For this toolkit the type of heat recovery covered is the heat that can be recovered from ventilation air.
For a healthy environment humans require an adequate levels of indoor ventilation. This is to remove unwanted
moisture and accumulated pollutants such as dust, carbon monoxide, carbon dioxide and volatile organic compounds
from internal air. There are many methods of providing adequate ventilation such as:

Natural ventilation by a combination of opening windows, background vents. In older buildings with low levels
of air tightness and insulation uncontrolled ventilation can be provided by infiltration through cracks and joints
in the building envelope.




Passive stack ventilation
Demand controlled extract ventilation
Positive input ventilation
Mechanical Heat Recovery Ventilation
All of the above methods can provide adequate fresh air to varying levels of accuracy. However, when the warm stale
air is removed from the building the fresh air which replaces it must be heated.
Fig1. Heat Recovery System With Air To Air Heat Exchanger (Source: Passivhaustagung.de)
Mechanical Heat Recovery Ventilation (MHRV) can be used to recover 75% to 95% of the energy required to heat the
incoming fresh air up to the temperature inside the building. Mechanical heat recovery is best done on a whole building
basis.
The system consists of the following main components:



Air ducts to remove air from wet rooms (kitchens & bathrooms)
Air ducts to supply fresh air to accommodation and work spaces
A central heat exchange unit with fans to remove stale air and supply fresh air (usually located in an attic)
The important aspects to be aware of when considering mechanical heat recovery ventilation are:


The building must be air tight with an infiltration test value of <5m3/hr/m2 at 50Pa for the system to be of
benefit
The occupant will have to clean the filters at the recommended intervals
Access to the filters is important (in attic or utility room)
The filters may need to be replaced occasionally therefore it is important to ensure they are available
and not overly expensive
o The system may need servicing to ensure balanced supply of air
Specific Fan Power (W/l/s) this figure should be kept to 1W/l/s or less
T
Summer bypass in summer the heat exchanger should not be used to allow night time air cool the building
The installed system must be commissioned and balanced for it to work properly
o
o




Installations should be designed by a qualified consultant and installed by a competent contractor as the layout and
workmanship of the ducting will affect how well the system performs.
In the UK Mechanical Heat Recovery Ventilation scheme must be install in accordance with current building
regulations.
Other forms of heat recovery, which are not used as much as MHVR are:


Heat recovery from hot waste water from hot water appliances (washing machines, dish washers and showers
etc.) to heat incoming water or air.
Heat recovery on flues of non-condensing boilers to pre heat water.
Trainenergy - Ventilation
Energy Savings Trust - Energy Efficient Refurbishment of Existing Housing
Energy Savings Trust - GPG268 Energy efficient ventilation in dwellings a guide for specifiers
Channel 4 - Overview of Ventilation Options Including Heat Recovery
Passive House Institute - Overview of ventilation for Passive Houses (Heat Recovery)
Residential Ventilation Association
Building Services Research and Information Association
Chartered Institution of Building Services Engineers
Technical Toolkit
Wood Stoves
2.2.5.5
New Build
Wood Stoves




o Solar hot water
o Heat pumps
o Biomass
The simplest and often most cost effective method of supplying renewable heat to a building is to use a wood stove.
When only wood is burned in a stove the energy is 100% renewable and carbon neutral.
*Note* For non-domestic buildings generally woodstoves would not be suitable for supplying the buildings heating
requirement. However, depending on the type of the building, its size and how the building is used, a woodstove may
provide a good solution in a non-domestic environment.
Wood stoves are much more efficient than open fires. Open fires have efficiencies of 25% to 30%, (i.e. 60% to 75% of
the fuel burnt is wasted) whereas wood stoves have efficiencies from 65% to 90%. A wood burning stove is a stove that
is optimised to burn wood, it is not a multi fuel stove. A stove that is optimised and certified to burn only wood will
operate at optimum efficiency when burning wood. Using other fuels may shorten the lifespan of a wood only stove.
There are two main types of wood stove:

Room heater without back boiler (to just heat the area in which it is installed)
Fig1. Wood Burning Stove (Source: Aruve)

Room heater with built in back boiler (to heat the area in which it is installed and back boiler to heat hot water
and or radiators)
Fig2. Wood Burning Stove with Back Boiler (Source: Renewable Energy Systems Integration Group)
Fuel types
Of the two types of wood stoves there are models which are designed to use wood logs or wood pellets as fuel.
Wood logs - It is important to use properly dried and seasoned wood logs. Freshly cut wood has high moisture content
(40 to 50%) and does not burn well or give out as much energy as when it is dry. If purchasing fresh logs (usually lower
price), the owner should store the logs stacked horizontally in a covered, tidy log pile with the bark facing upwards and
the cut ends exposed to air / wind. This will produce seasoned wood within one year. Wood logs should ideally be at
20% moisture content or lower to give best efficiency and rated outputs. Softwood and hard woods are both suitable,
soft woods are less dense, therefore the same weight but a larger volume of the fuel will be required to be burnt for the
same heat to be emitted to the space.
Benefits of wood logs:





Wood logs are sourced locally, whereas pellets are often traded internationally
Wood log stoves are simpler devices, therefore require less maintenance
Wood log fuel is cheaper than pellets
Wood log stoves offer a much closer resemblance to open fire flame, which is often preferred
Wood logs can be stored outdoors, wood pellets cannot
Wood pellets - Pellets are a very dry (8% Moisture Content) manufactured fuel, the pellets are made from sawdust,
which has been pressed into cylindrical pellets. For stoves they are supplied in convenient 10 to 20kg bags.
Benefits of wood pellets:




Wood pellet stoves are more automatic than log stoves and can be thermostatically controlled to maintain a
required temperature.
They result in less ash produced.
Wood pellet stoves are more contemporary looking than log stoves.
O
log stove does.
Regulations
Planning permission - Planning permission is not typically required to install a wood burning stove if the work is all
internal. If an outside flue is needed it will usually be permitted development if the conditions defined below are met.
o
o
o
Flues on the rear or side elevation of the building are allowed to a maximum of one metre above the
highest part of the roof.
If the building is in a designated area it is advisable to check with your local planning authority before a
flue is fitted.
In a conservation area or in a World Heritage site the flue should not be installed the principal or side
elevation if it would be visible from a highway.
Smokeless zones - If the building you plan to heat is in a smoke control area, you will be required to use an exempt
appliance. To establish if the building is located in a smoke controlled area contact your Local Authority.
Building Regulations -If you wish to install a wood burning stove then building regulations will apply.
SERVE Guide to stoves
British Flue and Chimney Manufacturers Association - Consumer Guidance on Wood log & pellet stoves
California Energy Commission - Wood Stove and Fireplace Guidance
HETAS - tested efficiencies of wood stoves
Biomass Energy Centre
Energy Saving Trust A B
G
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-Fuelled Heating
Technical Toolkit
Heating Controls
2.2.5.6
New Build
Heating Controls



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o Solar hot water
o Heat pumps
o Biomass
F
trolled effectively. Heating controls
are a very cost effective method of achieving energy savings and providing the required level of comfort.
Heating controls must allow the building occupant to regulate the time and temperature and location where heat is
required.
Fig1. Programmable Controller (Source: SEAI)
Heating controls in a typical building should include the following main components:





Room thermostat in two zones of the building. This can be set to the desired temperature.
Hot water thermostat: Mounted on the hot water tank, controls a valve on the heating coil.
Programmable controller: This is a device which allows the occupant to programme what times of the day and
what days of the week that each zone should be heated to the specified temperature. The controller should
have features such as boost buttons, to allow heat to be called on outside programmed times.
Valves to switch zones on and off depending on programmed time and temperature
I
tor can be controlled to maintain a lower temperature than the
room with the thermostat by using thermostatic radiator valves, which are simply installed at the radiator.
(Note do not install on radiator in room with wall thermostat as they may conflict)
Key considerations when specifying heating controls are:





The system must offer time, temperature and zone control, appropriate to the use of the building
The system must be usable by the occupants, training and guidance documentation should be provided
Maintenance of the system must be considered, if the system requires batteries for thermostats to
communicate to the controller, this must be made obvious to the user and instructions on how and when to
change them must be given
Reliability of the system is a consideration, some systems are wireless, they may be very effective, but if the
path of communication from the thermostat to the valve, controller or boiler is blocked by a large metal object
the signal may be lost
Boiler interlock must be provided, this means that when all zones are off, the boiler will be instructed not come
on and waste energy, even if the boiler return thermostat reads a low temperature. (This is necessary to
prevent cycling)
Regulations
Heating controls must be installed in compliance with Approved Document Part L of Building Regulations:
Carbon Trust - Building Controls & BMS
Energy Savings trust Thermostats and controls
National Energy Foundation - Guide on heating controls
The British Electrotechnical and Allied Manufacturers Association - Heating Controls Research report
Technical Toolkit
Solar Hot Water
2.2.5.7
New Build
Solar Hot Water




o Solar hot water
o Heat pumps
o Biomass
Solar hot water is also named solar thermal. This technology captures the energy from the sun to heat water. Solar
through the collector in copper pipes. The warmed fluid is then pumped through a heat exchanger coil inside a hot
water cylinder to heat the stored water. Temperature sensors link to a simple electronic controller, which determines
.
Solar thermal systems are almost always integrated with another heat source (e.g. a standard boiler), which tops up the
heat in the storage cylinder as required, during periods of low output. Twin coil cylinders are commonly used, with two
heat exchanger coils: the lower coil is connected to the solar thermal collector loop, and the upper one to the boiler
circuit.
Fig1. Solar Thermal System With A Twin Coil Cylinder (Source: Exenergy)
An alternative to the twin coil cylinder system is a dedicated single coil cylinder system where there are two or more
separate cylinders. In this type of system the solar thermal circuit supplies a single coil cylinder which provides preheated water to another cylinder which is connected to the boiler circuit.
Fig2: Solar Thermal System With A Dedicated Single Coil Cylinder (Source: Renewable Energy Solutions)
Panel Types
Two main types of solar thermal panel exist:
Flat Panels
This type appears flat similar to a dark black coloured pane of glass. This type consists of a looped grid of pipes behind
the dark glass, the pipes contain a heat transfer liquid, usually glycol, (similar to anti-freeze). This liquid is heated up to
very high temperatures (can be over 1000C) while it is pumped through the solar panel pipes.
Fig3. Flat Panels (Source: solarthermalworld.org)
The liquid is then pumped through a sealed heat transfer loop within the insulated domestic hot water tank (The glycol
never comes into direct contact with the water). This heats up the water in the hot water tank.
Evacuated Tube
Evacuated tube solar collectors work by a similar principle to flat panels above, however, they are more efficient per
unit area as they make greater use of low level sunlight and the tubular shape of the collectors ensures that an optimum
Fig4. Evacuated Tubes (Source: solardynamix.com)
Unglazed collectors
Unglazed collectors are also available which are suitable for low temperature application such heating water for
swimming pools.
Location
Mostly solar panels are roof mounted facing south at an angle of 30 to 45 degrees to the horizontal. It is acceptable to
mount solar panels on the ground using a frame; this has the benefit of allowing optimum tilt and azimuth. But the
significant disadvantage that possibly the collector will be located too far from the tank and significant heat could be
lost (even through well insulated pipes).
Solar panels should be mounted to face south where possible, however a small variation in this angle is acceptable if the
roof is not facing directly south, 15o to either side may be acceptable.
The optimum angle for solar collectors to the horizontal is in theory equal to the degrees of latitude of the coordinates
of the building.
If there is any shading present that would block a significant portion of the collector during the day as shadows move
across the collector, this would be a strong reason to decide not to install solar.
Sizing
Solar panels and their associated hot water tank must be sized to ensure the quantity of hot water produced by the
system closely matches the demand for hot water in the building. Therefore key design considerations may be:




The number of occupants The number of occupants will give an indication as to the required water, which will
allow the tank to be sized and then the panel to be sized
The type of hot water usage (i.e. showering, washing, can dishwasher and washing machine be connected to
use hot water from the tank?)
The schedule of hot water usage, is this spread out over the week or is it greatly concentrated on the
weekends?
The annual solar irradiance in the locality is a key consideration in sizing the required collector, the further
south countries have greater energy available from the sun, therefore they may require smaller collectors for
the same amount of hot water.
Design
Important design consideration to be included in the design of a system for safety reasons:



Ensure that there is an over heat arrangement which is correctly plumbed to a drain which in the event of a
power cut on a sunny day when there is no demand for hot water can if required allow some drain off from the
tank.
A professionally sized and plumbed heat dump is a safety requirement also, this could be a hot press radiator or
a towel radiator, these will take heat from the solar hot water system in the event that all the water in the tank
has been heated up and there is still hot fluid circulating. This must be set up so that it is not possible to close
valves to this heat dump.
Design and installation of solar panels should only be attempted by qualified and trained professionals. A list of
approved of installers for each technology should be consulted. In addition to this each customer should ask for
previous work references and check these diligently to ensure quality of workmanship and service is obtained.
Operation and Maintenance
Solar thermal is not a complicated technology but requires some simple on-going maintenance that the customer must
be aware of.


Solar panels required to be washed every year or six months if in a dusty location, this keeps performance levels
high.
T
this may be annual or at longer intervals.
It is possible to use solar thermal to heat water to provide space heating to low energy buildings, however this
application is expensive, complicated and not well established or readily commercially available.
European Solar Thermal Industry Federation
Solar Trade Organisation UK
Energy Saving Trust
REAL Renewable Energy Assurance Limited
Mircogeneration Certification Scheme
Technical Toolkit
Hot Water Controls
2.2.5.8
New Build
Hot Water Controls




o Solar hot water
o Heat pumps
o Biomass
Hot water in most buildings in UK is supplied by either combination boiler or a hot water tank. A combination boiler
heats water when required, supplying hot water directly from the boiler to the taps. A hot water tank is generally
heated by a coil, which is heated by the main heating system, or alternatively the water can be heated by an electrical
element.
Whatever method is used it is imperative that accurate controls are in place to ensure that:


Only as much water is heated as it required
Water is heated only for as long as necessary

The water that is heated is only heated to the required temperature
The controls used depend on the method used to heat the water:
Main Heating System
Where the water is heated by the main heating system such as a boiler or heat pump and stored in a hot water tanks it
should be controlled by the main heating controls. This is covered in the heating controls section of the toolkit. This
arrangement requires that a tank thermostat is installed and a motorised valve is wired to ensure than the tank
consumes no further energy when the water in the tank is hot enough or that the user programmed time controller
signals that hot water is not required at the particular time.
Where a combination boiler is used to heat the hot water, the hot water is heated and supplied on demand. The water
should only be heated to the required temperature which can be controlled at the boiler.
Electrical Immersion
Where water is not heated directly by a boiler an electrical element may be used. An immersion heater is mounted in
the top of the hot water cylinder. The heater contains an insulated electric resistance heater and a temperature sensor
to switch off the water when it reaches the require temperature. This arrangement requires electrical controls of which
a number exist.
*Note* Electrical immersions are usually the most expensive and carbon intensive method to heat water, especially if
not using night rate electricity.
Dual immersion heaters contain two separate elements; a short one and a second longer one. The short element heats
a small portion of the water at the top of the tank. The second longer immersion is provided to heat water at the
bottom of the tank, to supply large quantities of water when required. The duel immersion heater therefore offers a
choice as to how much water is heated up at any one time, ensuring that excess hot water is not heated when not
required.
Time Controls
Two types are common:
1. A timer which the user can set to heat water for the same period every day. This is useful if a regular pattern is
required. But can lead to wasted energy if the timing is forgotten about or if it is set for excessively long times.
2. A boost button, this is simply pressed by the user when hot water is required, it then heats up the water to the
set temperature and switches off after a pre-set time, thereby making it impossible for somebody to forget to
switch off the hot water.
It is important that whatever control is fitted that a tank thermostat is also in place to regulate the temperature of the
water in the tank. This will switch off the immersion if the water is hot enough.
*Note* While it is important to save energy by not over heating water, it is also important to ensure there is no risk
Legionella bacteria developing in the hot water system, differing best practice advice exists on this point but generally it
is suggested that water should be heated to 60oC for a period every week to ensure this risk is avoided.
Instantaneous Hot Water Units
An alternative method to obtaining hot water is to use an instant hot water heating unit, these are suited to situations
where:


Only a small amount of water is required every time hot water tap is used,
Situations where there is a very long run from the hot water tank to the tap, which requires a very long run off
period or where excessive energy would be lost by continuously circulating the water in the distribution
pipework.
They can be gas or more commonly electrically powered. The instant water heater is usually located under a sink or in a
cupboard. Some units can be plumbed to a number of taps in close proximity.
Heating and Hot Water Industry Council (HHIC)
Hot Water Association - Risk Assessment and Control Measures for Hot Water Systems
Energy Savings Trust Hot Water Energy Calculator
Energy Savings Trust - Thermostats and controls for electric systems
Energy Savings Trust - Thermostats and controls
Technical Toolkit
Cooling
2.2.5.9
New Build
Cooling




o Solar hot water
o Heat pumps
o Biomass
In Low Energy Buildings, the high level of insulation, reduced glazing on the north elevation and the increased glazing on
the south elevation can result in overheating. This can readily be remedied by using blinds over windows to block most
incoming solar radiation and by increasing natural ventilation. This strategy does require that occupants are proactive in
managing their environment and they operate windows and blinds in accordance to the conditions.
In commercial and industrial buildings a natural ventilation solution to overheating is the best as it does not result in
consumption of energy. In some situations due to design and layout where excessive solar gain occurs and thermal load
from high concentrations of humans and work equipment such as computers, servers and printers there may be a need
to provide forced cooling at different times of the year.
If this is required, the lowest energy options should be exhausted first:
1. Install external brise soleil, which are installed over windows to block the highest intensity sun light
2. Where a ventilation / air-conditioning system exists, consider running the fan at a higher rate, without any
chillers running and with 100% fresh air supply to the space, the higher air flow rate and no recirculation could
suffice in removing sufficient warm air.
3. If the above step is not adequate during operation hours, the air handling unit should be run the same as
above, but a night time cooling strategy should be attempted, which cools the building further at night by
forcing cool night air through the building at night. (This is effective where thermal mass is available)
4. If an energy consuming system is required, depending on the temperature required, absorption chilling is a very
energy efficient method of proving chilled air to at least a few degrees lower than outside. An absorption chiller
can work on excess heat (hot water or steam) if this is available as a by-product from some process on site.
5. Free cooling is possible as a low energy source, it is used in IT rooms a lot.
6. In some cases with very large buildings, cooling is required at one side and heating is required at the other. In
this case an air source heat pump is a very effective solution as some models are available that can use excess
heat in one location to provide cooling to another (the domestic hot water could also be heated using this
strategy)
7. As a very last resort individual DX refrigerant units may be used, these are not the most effective method of
cooling as they do not provide a whole building solution and they can become impossible to control centrally.
Carbon Trust - Heating, Ventilation and Air Conditioning (HVAC)
California Energy Commission - Evaporative Cooling
Energy Star
US Department of Energy - Cooling advice (In a Warm Climate)
Technical Toolkit
District Heating
2.2.5.10
New Build
District Heating




o Solar hot water
o Heat pumps
o Biomass
District heating (DH) is a very common and long established form of heating in continental Europe. The basis of district
heat is that all houses in an area are heated by one large central system. One DH plant may provide all the heat to a
town or city, however technically a DH plant may heat two or more properties.
The heat is transported as hot water pumped through very well insulated underground pipes, each building is
connected to the network, the heat is paid for per the number of
W
meter (same principle as electricity and gas).
Fig1: District Heating System (Source: Safege.com)
T
T
where usage is meas
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building. So DH is very flexible in that it can be used for any building heating system, whether it is radiators, underfloor
heating, air conditioned etc.
District Heat Customer Advantages:
1. Depending on the source of fuel being used, the customer can often get heat cheaper than they would do with
their own boiler.
2. Since the heat producing plant is often the responsibility of others, there is usually a back-up system in place
should the main plant fail. This ensures for a more secure supply of heat when compared to a heating system
where the user had their own boiler.
3. The customer could be provided with a renewable and possibly carbon neutral heat source.
4. District heat is often coupled with the generation of electricity through Combined Heat and Power, the DH pipe
network allows the waste heat from the generation of electricity to be used as a cheap heating source.
District Heat Overall Advantages:
1. Suited to larger renewable energy biomass technologies which use local wood chip and forestry by products
which are not always a suitable option at single building level
2. DH if powered by biomass is renewable and Carbon neutral
3. District heat allows biomass from local forests to be used to fuel the boiler, this creates local jobs and also the
money paid by the building owner for their heat stays in the local economy, which has many benefits for the
local economy, as direct and indirect jobs are created.
4. Where DH networks are available, this allows waste heat from Electricity Generation to be used. This makes
electricity generation much more efficient.
5. DH also encourages distributed generation, located close to the point of use (towns and cities). Therefore the
transmission losses are reduced and the grid is made more robust.
Euro Heat and Power
Trainenergy Guide to District Heating
FOREST - Biomass Boilers and District Heating
Solar District Heating - Solar District Heating Guidelines
Energy Savings Trust - Comprehensive guide to District Heating
Energy Savings Trust Rural District Heating Case Study
Energy Savings Trust Urban District Heating Case Study
Building Other Than Dwellings - Retrofit
Technical Toolkit
Electricity
Non Domectic Buildings
2.2.6
New Build
Electricity
NZEB Electricity



Minimise electricity consumption:
o Choose A-rated appliances
o Monitor energy use with Smart Meters if available and BMS systems
Choose a suitable renewable generator for your site:
o Wind
o PV
o CHP
o Hydro
Minimum of 40% electricity to be generated using renewable technologies
This Section outlines the following topics:
 Energy efficient electrical appliances
 Micro-generation & Auto-generation
 Smart Meters
 Energy Monitors
 BMS Systems
This section outlines methods of generating renewable electricity in buildings other than dwellings such as office,
commercial, industrial and leisure buildings. Before generating electricity through renewable sources, it is critical to
minimise electrical consumption, so that electricity is not wasted.
Consider upgrading old appliances - when it comes to replacing electrical appliances, A-rated appliances should be
chosen. The benefits of A-rated appliances is discussed by the Energy Savings Trust
Non Domestic Buildings Retrofit
The Energy Saving Trust provides a list of Energy Saving Trust Recommended products. This voluntary labelling scheme
tests products against strict criteria which have been set by an independent panel and are reviewed annually. The
scheme also recommends products in categories where there isn't an EU energy label available.
Micro-Generation And Auto Producers
The EPBD (2010) discusses requirements for retrofit buildings:
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major renovation works are to be undertaken, the building or the renovated part shall be upgraded to
meet the minimum energy performance requirements ........................ in so far as it is technically, functionally
and economically feasible
In terms of meeting minimum energy performance requirements, producing energy from renewable sources on-site or
nearby can help achieve this. However, the solution must be cost-optimal, meaning that the energy performance
solution must lie within the range of lowest cost for the lifetime of the solution, taking into account investment costs as
well as operational and maintenance costs.
Fig1. Cost Optimisation (Source: DECLG)
Micro-generation is generally defined as small-scale production of heat or electricity, for use at local level. The aim is
that individuals and organisations can produce enough energy to meet their needs. Micro-generation also refers to low
and zero carbon emitting technologies, due to the use of renewable energy sources as the primary fuel type.
Micro-generation is generally defined as small-scale production of heat or electricity, for use at local level. The aim is
that individuals and organisations can produce enough energy to meet their needs. Micro-generation also refers to low
and zero carbon emitting technologies, due to the use of renewable energy sources as the primary fuel type. Microgeneration is defined as up to 50kW.
An auto-producer is defined as someone who generates electricity on a single premises, essentially for their own
consumption. The generation and consumption must occur on a single site, which is in the legal ownership of the party
in question. The Maximum Export Capacity (MEC) can be up to twice the Maximum Import Capacity (MIC).
 Importing Auto-Producer, where the MEC is less than or equal to the MIC
 Exporting Auto-Producer, where the MEC is greater than the MIC.
Electricity producing micro/auto-generation technologies include:
 Photovoltaic solar panels
 Wind turbines
 Combined Heat & Power (CHP)
 Hydro
Smart Meters
In addition to European energy efficiency targets, there are a number of key EU legislative instruments, such as
Directive 2009/72/EC, which require that customers are properly informed of energy consumption and costs in realtime, allowing them to easily regulate energy use. Smart Metering is the ability to measure electrical consumption in
real-time, and can distinguish between imported and exported electricity.
In simple terms, a Smart Meter is a meter that monitors actual gas and electricity consumption in real-time, and feeds
this information back to the supplier, so that you are billed for your exact usage - there will be no more estimated bills.
It will replace current electricity and/or gas meters.
A Smart Grid is the development of the existing grid, adding better monitoring, analysis, control and communication
between generator, distributor and consumer, in order to maximise the efficiency of the electricity network. The
European Technology Platform SmartGrids (ETP), which is supported by the European Commission, defines Smart Grid
as:
- generators,
consumers and those that do both in order to efficiently deliver sustainable, economic and secure electricity supplies"
Different price rates can also be set in order to encourage electricity consumption at off-peak times and discourage use
at peak times. Time varying electricity prices indicate to the consumer that cost of producing electricity varies in line
with demand. Therefore, if certain tasks can be put off to non-peak times, then it saves electricity production at higher
rates, which in turn saves the customer money as they are purchasing at cheaper rates. The Commission of Energy
Regulation (CER) carried out a smart metering pilot scheme.
Fig2. Time Varying Electricity Prices During Smart Metering Pilot Scheme (Source: Commission Of Energy Regulation)
Energy Monitors
The terms Smart Meter and Energy Monitor can get mixed up and be confusing. An energy monitor is a much simpler
device compared to the Smart Meter. The monitor gives the consumer an idea of electricity consumption in real time,
and an idea of cost if a unit price has been entered into the monitor. They are simple hand-held or table top devices.
They do not feed information back to the supplier.
Fig3. Energy Monitor (Source: CER)
Building Management Systems
Building Management Systems (BMS) are computer-based control systems used in buildings to control and monitor the
ventilation, lighting, power systems, fire systems, and security
systems.
BMS can show where and when energy is being used. Once energy use is known, it is easier to control see where energy
can be saved by minimising the unnecessary use of systems. For example, automatic controls can be put in place to
switch off all electrical equipment when not required, such as when an office or school is closed. It can also help control
internal temperatures by switching off heating or air handling units when comfortable levels have been reached.
Fig4. Building Management Systems (Source: Method Statement)
Come On Labels EU Energy Labels
Micro-Generation Europe
Energy Saving Trust - Smart Meters
Which - What Is An Energy Monitor?
Which - What Is A Smart Meter?
Video Links:
EUTube - Electricity Price Per kWh
EUTube - Electricity In The EU Sparking A Green Economy
Which - Difference Between Smart Meters And Energy Monitors
Building Other Than Dwellings - Retrofit
Technical Toolkit
Photovoltaic Panels
2.2.6.1
New Build
Photovoltaic Solar Panels
NZEB Electricity (RND)



o Wind
o PV
o CHP
o Hydro
Photovoltaic panels are solar panels that convert solar radiation or energy into an electrical current. When sunlight is
absorbed by a material known as a semiconductor, the construction of the photovoltaic cells causes electron excitement
within the PV materials when sun shines on the cell. This movement of electrons produces a DC voltage, and current
then flows, generating electricity. PV systems are typically constructed from purified crystalline silicon (a
semiconductor) and covered in glass. Small PV cells are linked together to form modules (or panels) which are in turn
linked to form PV arrays. This property of the material is known as the photoelectric effect.
Non Domestic Buildings - New Build
Fig1. Photovoltaic Solar Panel Diagram (Source: Ron Curtis and MrSolar.com)
Fig2. A 10kWp photovoltaic system installed to a community centre in mid-Wales (Source: Severn Wye Energy
Agency)
Different types of silicon cells used in these modules will yield slightly differing results:

Polycrystalline cells these use a cheaper form of silicon with varying sizes and orientations of crystallite grains.
Performance is lower for a given unit size. Polycrystalline cells typically have a speckled blue-ish appearance.

Monocrystalline cells these are derived from a single-crystal slice of refined silicon with a uniform and
unbroken grain structure. Performance is higher, but the resulting modules are inevitably more expensive.
Monocrystalline cells typically have a smooth grey or black uniform appearance.

Hybrid cells these often comprise a monocrystalline layer in addition to an amorphous silicon layer (the same
material used in flexible thin-film PV systems), which can respond better to diffuse light. Hybrid panels generally
offer the highest performance, but again, this is reflected in their price.
System Types a wide range of building-integrated PV systems is available, including solar tiles, modules, shingles and
flexible modules integrated into cladding or roofing materials. Rectangular PV modules are by far the most common
system type, with panels that are typically 1.5 x 0.8m in size.
Panel Location the siting requirements for solar PV panels are similar to those for solar thermal collectors. The most
suitable location is a south-facing roof, with an angle of 30 50° above the horizontal. But the roof does not actually
have to face due south; even for south east or south west roofs (45° off due south) the fall-off in solar capture amounts
to only a few percent. PV systems facing due east or west, on shallow-incline roofs, can also perform reasonably well.
On flat roofs, panels can be mounted on frames at the optimum angle.
Fig3. Table showing the difference in panel performance when tilt and orientation are changed (Source: Severn Wye
Energy Agency)
Solar Maps
S
A
map of the UK is shown below, based on data from the Met Office. This gives a representation of the amount of solar
energy in kWh/m2 that hits the UK at different times of the year.
Fig4. UK Solar Maps (Source: Met Office)
Solar GIS is an on-line database, giving access to solar data via interactive maps. It also contains PV simulation software.
Solar GIS
Similar solar irradiation maps and other solar irradiance data can be found at the European Commission Joint Research
Commission. This website will also calculate the amount of solar electricity potential for a specific site or location
chosen:
European Joint Research Commission Solar Irradiation Maps
Energy Generation
A typical well-sited solar PV system in mid-Wales can generate 830-890 kWh per year, for each kWp of installed
capacity. A system sized at the top end of the highest feed-in tariff band, i.e. just below 4 kWp, would therefore be
expected to generate around 3,320 kWh annually. Around 75% of this output will occur in the seven months from
March September inclusive; the remaining five months will produce the other 25% of annual output.
PV Systems
There are two main PV systems:
 Grid-connection systems where the electricity produced is exported to the grid at a set price. Here the grid is
used as a storage facility, with the electricity generated being exported to the grid at a set price, and electricity
being used on the site being imported from the grid at another price. The payment for exporting to the grid
helps offset costs of electricity being purchased to use on site.

Stand-alone systems where the electricity produced is directly used on-site. Any extra electricity required by
the site is imported from the grid. However, any excess electricity generated is not exported to the grid. In this
case it can either be stored on site in form of batteries, or used for charging items such as electric vehicles.
Energy Saving Trust - PV
European Photovoltaic Industry Association
Train Energy - Photovoltaics
PV Resources
PVTrin Installer Certification
PVGIS - European solar radiation website
BRE National Solar Centre
BRE Installation of PV
BRE - Photovoltaics Field Trial
Solar Trade Association
Centre Alternative Technology - PV
Video Links:
YouTube Video -The Photovoltaic Effect
YouTube Video - Introduction to Photovoltaics
US Department of Energy: Photovoltaics - A Diverse Technology
Non Domestic Dwelling New Build
Technical Toolkit
Wind
2.2.6.2
New Build
Micro and Auto Wind
NZEB Electricity (NBND)



o Wind
o PV
o CHP
o Hydro
Micro-wind turbines are small-scale wind turbines, designed to produce electricity for localised use. A wind turbine
converts kinetic energy into mechanical energy. T
dynamo to generate an electrical current. In a micro turbine, the Direct Current is either stored in a bank of batteries, or
sent through an inverter, which transforms the Direct Current into an Alternating Current suitable for use in the mains
supply of a house or business.
Turbine siting
The turbine siting is critical siting when considering a wind turbine. There are many factors to consider, which are
outlined below:
Wind speed Wind speed is the starting point when deciding on the viability of the wind turbine project. An initial guide
to average local wind speeds can be found on the NOABL national wind database (see further Information at the end of
this document), which has kilometre grid square resolution. Entering a postcode or grid reference will produce the
average wind speed at 10m above ground level. A level of at least 5.0 m/s is required for a viable scheme. Wind maps
show the average wind speeds at certain heights above ground level across Europe. The UK has some of the highest
wind speeds, and therefore great potential to produce energy from the wind. However, local factors can have a
significant affect so it is vital to consider these. Ultimately, the only way to gain an accurate picture is to install a wind
monitoring mast at the proposed site, ideally for 6-12 months.
Fig1. European Wind Speed Map (Source: European Wind Atlas)
The wind speed at the exact height of the chosen wind turbine can then be calculated using the Shear Wind Formula:
The roughness height is the height above ground where the wind velocity is 0m/s, and differs depending on terrain type.
Terrain & obstacles Wind turbines are strongly affected by local obstructions that produce wind shadowing or
turbulence. The ideal site is an elevated position with clear, exposed views to the prevailing wind direction (west/south
west), and no obstacles such as trees or buildings upstream within at least 10 times the proposed turbine hub height.
Proximity of connection point Ground works and cabling connections (which are generally trenched underground)
represent a substantial portion of overall turbine installation costs. Cabling costs are very site-specific, but
unsurprisingly, long cable runs add to the costs, as do crossings of roads, driveways or yards to reach the electrical
connection point.
Noise All wind turbines generate noise, and the impact of this on nearby dwellings and other buildings must be
considered. There is a wealth of guidance available on this, but noise is a sensitive issue, since perceptions are very
subjective.
Visual impact As with noise, this tends to be a very subjective issue. The visual impact of the site has to be considered
through consultation with neighbours and local stakeholders.
Environment Small wind turbines have a low environmental impact, and you will rarely be required to provide a full
environmental impact assessment (EIA) to the local authority. But they may require certain aspects be assessed; such as
bird or bat impacts. It is important to consult your local planning officers early on to determine what they require to be
submitted as part of a planning application for a wind turbine.
System Types
There are some technical differences amongst small-scale wind turbine models, but the most common configuration is a
horizontal axis turbine with a 3-bladed rotor, as this is the optimum balance point between aerodynamic and structural
efficiency. This is attached to a hub, mounted at the top of a hinged steel monopole, allowing the whole turbine to be
lowered easily to the ground for maintenance. There are some twin blade turbine models on the market, and taller
poles may be multi-sectioned
T
ind direction. There are also
vertical axis helical turbines available, which have certain advantages in urban settings or areas of high wind turbulence.
Horizontal Axis Wind Turbine (HAWT)
 Blade and motor positioned on top of the support column
 Blades rotate in-line with the column
 Typical arrangement is a 3-blade turbine
 Blades must face into the wind in order to turn
Vertical Axis Wind Turbine (VAWT)
 Rotor shaft arranged vertically
 Blades spin around the support column
 Blades do not have to face into the wind
 Suitable for locations where wind direction is variable
 Suitable for roof-top mounting
Fig2. Horizontal and Vertical Axis Turbines (Source: Hill Country Wind Power)
Turbine Systems
There are two types of turbine system grid-connection systems and stand-alone systems. In grid-connection systems the
surplus electricity produced by the turbine is exported to the grid. The grid is used as a storage facility, with the
electricity generated being exported to the grid at one price, and electricity used on site being imported from the grid at
another price. Payment for exporting to the grid helps offset costs of electricity being purchased to use on site. In
stand-alone systems the electricity produced is directly used on-site. Any excess electricity generated cannot be
exported to the grid. In this case it can either be stored on site in form of batteries, or used for charging items such as
electric vehicles. Any extra electricity required by the site is imported from the grid.
Fig3. Stand Alone Wind Turbine (Source: Greenviron)
Fig4. Grid Connected Wind Turbine (Source: David Darling)
Turbine Power Output - Energy Generation
Generally, wind speeds must exceed 2.5m/s - 3m/s before gaining any electrical output from the turbine. The output of
a wind turbine is very obviously dependent on the local wind regime as small differences in annual average wind speeds
can make a very significant difference to annual output. As wind speed increases the turbines power output increases,
there is a cubic relationship between wind velocity and power output:
For example, for a density of 1.225kg/m3, and rotor diameter of 6m, at wind speed of 2.5m/s the power output will be:
P
P = 270kw
2
) *2. 53
If the wind speed increases to 5m/s the power output will be:
P
P = 2165kw
2
) * 53
Therefore, doubling the wind speed multiplies the power output by 8, showing that even a small change in wind speed
can cause a significant increase in power output.
The amount of electricity produced by a wind turbine is, therefore, dependant on three things:
1. Wind speed the faster the wind speed, the larger the power output
2. Swept area the larger the blade diameter, the larger the swept area
3. Height above ground the higher above ground, the faster the wind speed
To calculate the estimated power output from a wind turbine, the probability of a particular wind speed occurring must
be taken into account. The Weibull Curve must be established for each average wind speed at a particular site. The
Weibull shape parameter is generally around 2 in Northern Europe. A Weibull plotter is available from:
Renewable Energy Concepts - Weibull plotter
Danish Wind Industry Association - Weibull Distribution Plotter
The Weibull curve leads to the Power Density Curve for a given turbine. This is the actual power output at each wind
speed, which, together with the probability of a particular wind speed occurring, will give a total estimated power
output for a turbine at the given location.
Danish Wind Industry Association - Power Density Curve
Danish Wind Industry Association - Power Calculator
Manufacturers will produce power curves for each individual wind turbine on the market. Look up manufacturer
website for further information. Similarly, RETScreen contains power curves for a large number of manufacturers and
turbines models.
T
the wind to mechanical energy using a wind turbine.
B
L
kinetic energy in
Fig5. Typical Wind Turbine Power Output (Source: Wind Power Programme)
There are a number of sites where you can do basic power calculations, in order to get an initial idea of the potential
power output for your location:
Wind Power Calculator
Wind 101 - Wind Turbine Comparison Calculator
For More Information On Wind Turbine Calculations:
Danish Wind Industry Association
Good Practice Wind
Intelligent Energy Europe WINEUR Project - Urban Wind Turbines
Carbon Trust - Small Scale Wind
US Department of Energy - Wind Turbine Basics
Wind Power Calculator - Wind Energy How it Works
Microgeneration Certification Scheme - Approved Products and Installers
Renewable UK - Small and Medium Scale Wind
Centre Alternative Energy
Renew-Reuse-Recycle -Wind Generation Data
Renewables Guide - Wind Calculator
Natural Energy - Wind Speed
Video Links:
YouTube Video - Wind Turbine Basics
YouTube Video - W
W
T
Energy Saving Trust - Wind turbine
Technical Toolkit
CHP
2.2.6.3
New Build
Micro and Auto Combined Heat and Power



o Wind
o PV
o CHP
o Hydro
Combined heat and power (CHP), also known as co-generation, is the simultaneous production of heat and electricity
from a single fuel source such as natural gas, biomass, biogas, coal or oil. CHP is only classed as a renewable energy
generator if the main source of fuel is a biofuel. T
because it is more efficient than just burning a fossil fuel from the national grid. The system generates electricity,
capturing the normally wasted heat produced during this process, and uses it as space and hot water heating source.
Micro-CHP is defined as less than 50kWe (kilo Watt electric) in the EU Directive 2004/08.
B
CHP
USA Environmental Protection Agency - Basics of CHP
Energy Saving Trust - How Does Micro CHP Work?
Fig2. Comparing Efficiency of Conventional and Electricity Generation to CHP (Source: Sustainable Energy Authority of
Ireland)
T
CHP
thermal efficiency). This calculation provides a comparison between the heat and energy output of the system, and the
fuel consumed during the process. CHP with high thermal outputs generally fall within the range of 60 - 85% efficiency.
More information on calculating efficiency:
US EPA - Calculating CHP Efficiency
Types of CHP Systems
There are a number of different CHP unit types:

Reciprocating engines - conventional internal combustion engines coupled with a generator and heat
exchangers to recover the heat of the exhaust gases

Stirling engines - thermal engines where the heat is generated externally (external combustion engines). Also
equipped with a generator and heat exchanger(s)

Micro gas turbines - small gas turbines with electric power output up to 300kWe

Organic Rankine Cycle (ORC) - similar to a conventional steam turbine, except the fluid that drives the turbine is
a high molecular mass organic fluid

Fuel cells - electrochemical energy converters similar to primary batteries.
BUILDUP - Micro CHP, State of the Art
RETScreen - Co-generation chapter on CHP types and efficiencies
Energy Management Training - Co-generation paper on CHP principles and types
Microchap.info - Introduction to Micro CHP
Future for Rural Energy in Europe - CHP
Building & Engineering Services Association - Micro CHP
Department of Energy and Climate Change - CHP Focus
Combined Heat and Power Association
The European Association for the Promotion of Cogeneration
B&ES TR37 - 'Installation of CHP'
Carbon Trust - Emerging Micro-CHP Technology
Electrical Safety Council - Connecting a Microgeneration System to a Electrical Installation
Energy Saving Trust - CHP
Videos:
YouTube Video - Co-generation CHP
Technical Toolkit
Hydropower
2.2.6.4
New Build
Hydropower



o Monitor energy use with Smart Meters and BMS systems
o Wind
o PV
o CHP
o Hydro
Hydropower is the power generated from naturally flowing water. The energy from the flow of water is transferred into
electricity, in a similar way to how energy in wind is transferred to electricity by a wind turbine. A micro-hydro scheme
typically produces up to 100kW.
Compared to other micro-generating systems, hydro has the following advantages:





Constant supply of electricity
Low environmental impact
High energy potential for relatively low flow/speed
No noise pollution
Indigenous and clean source of fuel
In terms of deciding to put in a micro-hydro to help power your new building, the main issue is availability and proximity
to water. A micro-hydro will not be suitable or possible for the majority of non-domestic buildings in the United
Kingdom. However, if you are building near a river or water source, then micro-hydro is something that should be
considered.
Types Of Micro-Hydro Systems
The amount of head available tends to determine the type of micro-hydro system that is best suitable, please see figure
I
L H
Fig1. Diagram Showing Suitable Hydro Types For Low And High Head Schemes (Source: Department Of
Communications, Energy And Nature Resources Ireland)
There are three main types of hydro-power schemes:
Impounded/Dammed
An impounded or dammed hydro system is usually large scale, water is stored in a reservoir using a dam. The water is
then released through the penstock (delivery pipes) to the turbine (power generator).
Fig 4. Pumped Hydro System (Source: Creighton University)
Hydro Power Output
The energy produced by water in comparison to other renewable sources is substantial, due to the density of water.
Similar to wind, the energy that can be harnessed is a factor of the density of the material. The density of wind is in the
region of 1.225kg/m3, whereas the density of water is in the region of 1000kg/m3. Therefore, the same mass of water
would produce roughly 1000 times the power compared with the same mass of air. The amount of power from a hydro
scheme can be calculated using the following formula:
As gravity and density of water are constants, to maximise the amount of power being produced, the head and flow of
the water can be
T
T
more power can be generated. The flow is the speed of water multiplied by the area it must travel through.
Fig 5. Hydropower System Diagram (Source: NaRural Energy)
Therefore, to estimate the potential of your water source, you must measure:
 the head the vertical distance the water falls, which is equal to the difference in height between the intake
pipeline and the hydro turbine
 the flow volume of water passing through the designated area every second
There are a number of on-line calculator tools and software that can be used to calculate the estimated power output
from a hydro system.
Hydroxpert - Power Calculator
Engineering Toolbox - On-line Hydropower Calculator
The IEE Funded Splash Project produced a set of guidelines in relation to micro-hydro development. It outlines the
innovations, technical issues, environmental issues, and provides an economic analysis for micro-hydro:
SPLASH - Guidelines For Micro Hydropower Development
SPLASH - Factsheets
European Small Hydro Association - L
G
O H T D
AS
H
European Small Hydro Association
European Small Hydro Association - Checklist On Small Hydro-Power Pre-Feasibility Study
Stream Map - European Hydro Energy, Market & Policy Data
RENET - EU/India Technology Transfer Introduction To Hydro Energy
US Department Of Energy - Hydro Plant Types
British Hydro Association
Energy Saving Trust Guide To Hydro Power
Site
Environment Agency
Micro Hydro Association
Video Links:
Energy Saving Trust -Animation
YouTube Video - Micro Hydro How It Works
Technical Toolkit
Funding
2.2.6.5
New Build
Funding



o Choose A-rated appliances or Triple-E products
o Wind
o PV
o CHP
o Hydro
Renewable Electricity
The prior grant-based support mechanism in the UK was replaced in 2010 by a system based on the European REFIT
model (Renewable Energy Feed-In Tariff), already common in other EU countries. The UK Feed-In Tariffs (FITs) pays a
price for all electricity generated, with rates guaranteed and index-linked.
Feed in tariff payments come in two parts.
1. The generation tariff - This is a payment per unit (measured in kWh) of electricity generated. For every kWh
T
W
meter installed along with the system.
2. The export tariff - This is a payment per unit (kWh) of electricity that is exported back to the national grid.
Any units that are not used directly by the householder will automatically be exported to the grid. Most
systems in the UK are not currently fitted with a meter that measures the amount of electricity exported,
and it is therefore deemed to a set amount (50% of total generation).
FITs are available for a variety of electricity producing technologies including Solar PV, Wind turbines, micro Combined
Heat and Power (CHP) up to 2kW and Hydroelectric. The FITs are received for the tariff lifetime and this varies
depending on the technology. The rates available vary by technology and reviewed quarterly. To receive the full feed in
tariff rates for PV systems installed on properties an Energy Performance Certificate rated a mini
D
is required, otherwise a lower tariff applies. Please note that the normal exemptions for Energy Performance
Certificates under the Energy Performance of Buildings Directive do not apply to Feed-In Tariffs applications, Feed-In
Tariffs have different set of exemptions for further information see Ofgem website. Rates are paid for all generation,
including what you use; a export bonus applies for units sent to the grid (now for all technologies) this is typically
deemed at 50%. For current FITs rate visit the Ofgem website.
Ofgem - Feed In Tariffs (FIT)
Carbon Trust Feed In Tariffs
Energy Saving Trust Feed In Tariffs
Microgeneration Certification Scheme (MCS)
Technical Toolkit
Planning and Grid
2.2.6.6
New Build
Planning Regulations & Grid Connection (NBND)



o Choose A-rated appliances or Triple-E products
o Wind
o PV
o CHP
o Hydro
Planning Regulations
Under the Town and Country Planning Act 1990 local planning authorities in the UK are responsible for renewable and
low carbon installations up to 50 megawatts installed capacity. Renewable and low carbon developments over 50
megawatts capacity will be considered by the Secretary of State for Energy under the Planning Act 2008.
Microgeneration is often permitted development and may not require an application for planning permission.
The below information on planning regulations for individual renewable technologies has been taken from the Planning
Portal and was correct at the time of when this document was created. The guidance on planning regulations for
individual renewable technologies refers to planning regulations in England, please view the Planning Portal website is
Welsh guidance http://www.planningportal.gov.uk/permission/.
Micro PV
In many cases installing solar panels on non-domestic land is likely to be considered 'permitted development' with no
need to apply to the council for planning permission. There are, however, important limits and conditions which must
be met to benefit from the permitted development rights (see below).
Non-domestic land for the purposes of these permitted development rights is broad and can include businesses and
community buildings.
You may wish to discuss with the local planning authority for your area whether all of the limits and conditions will be
met.
Solar panels mounted on a non domestic building
All the following conditions must be observed:


Panels should be sited, so far as is practicable, to minimise the effect on the external appearance of the building
and the amenity of the area
When no longer needed for microgeneration panels should be removed as soon as reasonably practicable
All the following limits must be met:








Solar panels installed on a wall or a pitched roof should project no more than 200mm from the wall surface or
roof slope
Where panels are installed on a flat roof the highest part of the equipment should not be more than one metre
above the highest part of the roof (excluding the chimney)
Equipment mounted on a roof must not be within one metre of the external edge of the roof
Equipment mounted on a wall must not be within one metre of a junction of that wall with another wall or with
the roof of the building
The panels must not be installed on a listed building or on a building that is within the grounds of a listed
building
The panels must not be installed on a site designated as a scheduled monument
If the building is on designated land* the equipment must not be installed on a wall or a roof slope which fronts
a highway
The capacity of the system must not exceed 45kW thermal or 50kW electrical generation
Stand alone solar panel installations in the grounds of a non-domestic building
All the following conditions must be observed:


Panels should be sited, so far as is practicable, to minimise the effect on the amenity of the area
When no longer needed for microgeneration panels should be removed as soon as reasonably practicable
All the following limits must be met:







Only the first stand alone solar installation will be permitted development. Further installations will require
planning permission from the local authority.
No part of the installation should be higher than four metres
The installation should be at least 5m from the boundary of the property.
The size of the array should be no more that 9 square metres or 3m wide by 3m deep.
Panels should not be installed within the boundary of a listed building or a scheduled monument.
If the property is in a designated area* no part of the solar installation should be nearer to any highway
bounding the grounds of the property than the part of the building that is nearest to that highway.
The capacity of the system must not exceed 45kW thermal or 50kW electrical generation.
* Designated land includes national parks, Areas of Outstanding Natural Beauty, conservation areas and World Heritage
Sites.
Note - If you are a leaseholder you may need to get permission from your landlord, freeholder or management
company.
Building Regulations
If you wish to install a solar panel on your roof building regulations will normally apply. The ability of the existing roof to
carry the load (weight) of the panel will need to be checked and proven. Some strengthening work may be needed.
Building regulations also apply to other aspects of the work such as fire protection and weather proofing. It is advisable
to contact an installer who can provide the necessary advice.
Micro Wind Turbines
What are the particular planning considerations that relate to wind turbines?
The following questions should be considered when determining applications for wind turbines:

How are noise impacts of wind turbines assessed?
T
T
(ETSU-R-97) should be used by local
planning authorities when assessing and rating noise from wind energy developments. Good practice
guidance on noise assessments of wind farms has been prepared by the Institute Of Acoustics. The
Department of Energy and Climate Change accept that it represents current industry good practice and
endorses it as a supplement to ETSU-R-97. It is available on the Department of Energy and Climate
C

.
Is safety an issue when wind turbine applications are assessed?
o
Safety may be an issue in certain circumstances, but risks can often be mitigated through appropriate
siting and consultation with affected bodies:
o
Buildings Fall over distance (i.e. the height of the turbine to the tip of the blade) plus 10% is often
used as a safe separation distance. This is often less than the minimum desirable distance between wind
turbines and occupied buildings calculated on the basis of expected noise levels and due to visual
impact.
o
Power lines National Grid, and/or the relevant Distribution Network Operators will be able to advise
on the required standards for wind turbines being separated from existing overhead power lines.
o
Air traffic and safety Wind turbines may have an adverse affect on air traffic movement and safety.
Firstly, they may represent a risk of collision with low flying aircraft, and secondly, they may interfere
with the proper operation of radar by limiting the capacity to handle air traffic, and aircraft instrument
landing systems. There is a 15 kilometre (km) consultation zone and 30km or 32km advisory zone
around every civilian air traffic radar, although objections can be raised to developments that lie beyond
the 32km advisory zone. There is a c.15km statutory safeguarding consultation zone around Ministry of
Defence aerodromes within which wind turbine proposals would be assessed for physical obstruction.
See the Town and Country Planning (safeguarded aerodromes, technical sites and military explosives
storage areas) direction 2002. Further advice on wind energy and aviation can be found on the Civil
Aviation Authority and National Air Control Transport Services websites.
o
Defence Wind turbines can adversely affect a number of Ministry Of Defence operations including
radars, seismological recording equipment, communications facilities, naval operations and low flying.
Developers and local planning authorities should consult with the Ministry of Defence if a proposed
turbine is 11 metres (m) to blade tip or taller, and/or has a rotor diameter of 2m or more.
o
Radar In addition to air traffic radar, wind turbines may affect other radar installations such as
weather radar operated by the Meteorological Office.
o
Strategic Road Network The Highways Agency / Department for Transport have produced advice for
siting wind turbines safely in relation to the strategic road network titled T
and

.
Is interference with electromagnetic transmissions an issue for wind turbine applications?
Wind turbines can potentially affect electromagnetic transmissions (e.g. radio, television and phone
signals). Specialist organisations responsible for the operation of electromagnetic links typically require
100m clearance either side of a line of sight link from the swept area of turbine blades. OFCOM acts as a
central point of contact for identifying specific consultees relevant to a site.

How can the risk of wind turbines be assessed for ecology?
Evidence suggests that there is a risk of collision between moving turbine blades and birds and/or bats.
Other risks including disturbance and displacement of birds and bats and the drop in air pressure close
to the blades which can cause barotrauma (lung expansion) in bats, which can be fatal. Whilst these are
generally a relatively low risk, in some situations, such as in close proximity to important habitats used
by birds or bats, the risk is greater and the impacts on birds and bats should therefore be assessed.
Advice on assessing risks is available from N

E
.
How should heritage be taken into account in assessing wind turbine applications?
As the significance of a heritage asset derives not only from its physical presence, but also from its
setting, careful consideration should be given to the impact of wind turbines on such assets. Depending
on their scale, design and prominence a wind turbine within the setting of a heritage asset may cause
substantial harm to the significance of the asset.

Is shadow flicker and reflected light an issue for wind turbine applications?
o
Under certain combinations of geographical position and time of day, the sun may pass behind the
rotors of a wind turbine and cast a shadow over neighbouring properties. When the blades rotate, the
O
either side of north, relative to the turbines can be affected at these latitudes in the UK turbines do
not cast long shadows on their southern side.
o
Modern wind turbines can be controlled so as to avoid shadow flicker when it has the potential to
occur. Individual turbines can be controlled to avoid shadow flicker at a specific property or group of
properties on sunny days, for specific times of the day and on specific days of the year. Where the
possibility of shadow flicker exists, mitigation can be secured through the use of conditions.
o
Although problems caused by shadow flicker are rare, where proposals for wind turbines could give rise
to shadow flicker, applicants should provide an analysis which quantifies the impact. Turbines can also
cause flashes of reflected light, which can be visible for some distance. It is possible to ameliorate the
flashing but it is not possible to eliminate it.

How to assess the likely energy output of a wind turbine?
As with any form of energy generation this can vary and for a number of reasons. With wind turbines
the mean wind speed at hub height (along with the statistical distribution of predicted wind speeds
about this mean and the wind turbines used) will determine the energy captured at a site. The simplest
way of expres
T
with location and even by turbine in an individual wind farm. This can be useful information in
considering the energy contribution to be made by a proposal, particularly when a decision is finely
balanced.

How should cumulative landscape and visual impacts from wind turbines be assessed?
o
Cumulative landscape impacts and cumulative visual impacts are best considered separately. The
cumulative landscape impacts are the effects of a proposed development on the fabric, character and
quality of the landscape; it is concerned with the degree to which a proposed renewable energy
development will become a significant or defining characteristic of the landscape.
o
Cumulative visual impacts concern the degree to which proposed renewable energy development will
become a feature in particular views (or sequences of views), and the impact this has upon the people
experiencing those views. Cumulative visual impacts may arise where two or more of the same type of
renewable energy development will be visible from the same point, or will be visible shortly after each
other along the same journey. Hence, it should not be assumed that, just because no other sites will be
visible from the proposed development site, the proposal will not create any cumulative impacts.

What information is needed to assess cumulative landscape and visual impacts of wind turbines?
In identifying impacts on landscape, considerations include: direct and indirect effects, cumulative impacts
and temporary and permanent impacts. When assessing the significance of impacts a number of criteria
should be considered including the sensitivity of the landscape and visual resource and the magnitude or
size of the predicted change. Some landscapes may be more sensitive to certain types of change than
others and it should not be assumed that a landscape character area deemed sensitive to one type of
change cannot accommodate another type of change.
In assessing the impact on visual amenity, factors to consider include: establishing the area in which a
proposed development may be visible, identifying key viewpoints, the people who experience the views
and the nature of the views.
The English Heritage website provides information on undertaking historic landscape characterisation and
how this relates to landscape character assessment.
The bullets below set out the type of information that can usefully inform assessments.
Information to inform landscape and visual impact assessments
o
A base plan of all existing windfarms, consented developments and applications
received, showing all schemes within a defined radius of the centre of the proposal
under consideration
o
For those existing or proposed windfarms within a defined radius of the proposal under
A
influence is the area from which a development or other structure is theoretically
visible). The aim of the plan should be to clearly identify the zone of visual influence of
each windfarm, and those areas from where one or more windfarms are likely to be
seen
o
The base plan and plan of cumulative zones of visual influence will need to reflect local
circumstances, for example, the areas covered should take into account the extent to
which factors such as the topography and the likely visibility of proposals in prevailing
meteorological conditions may vary
o
Maps of cumulative zones of visual influence are used to identify appropriate locations
for visual impact studies. These include locations for simultaneous visibility assessments
(i.e. where two or more schemes are visible from a fixed viewpoint without the need for
an observer to turn their head, and repetitive visibility assessments (i.e. where the
observer is able to see two or more schemes but only if they turn around)
o
Sequential effects on visibility occur when an observer moves through a landscape and
sees two or more schemes. Common routes through a landscape (e.g. major roads; long
proposals impact on them can be assessed
o
Photomontages showing all existing and consented turbines, and those for which
planning applications have been submitted, in addition to the proposal under
consideration. The viewpoints used could be those identified using the maps of
cumulative zones of visual influence. The photomontages could be annotated to include
the dimensions of the existing turbines, the distance from the viewpoint to the different
schemes, the arc of view and the format and focal length of the camera used
o
At the most detailed level, description and assessment of cumulative impacts may
include the following landscape issues: scale of development in relation to landscape
character or designations, sense of distance, existing focal points in the landscape,
skylining (where additional development along a skyline appears disproportionately
dominant) and sense of remoteness or wildness

Decommissioning wind turbines
Local planning authorities should consider using planning conditions to ensure that redundant turbines
are removed when no longer in use and land is restored to an appropriate use.
Micro Hydro
What are the particular planning considerations that relate to Hydropower?
Planning applications for hydropower should normally be accompanied by a Flood Risk Assessment. Early engagement
with the local planning authority and the Environment Agency will help to identify the potential planning issues, which
are likely to be highly specific to the location. Advice on environmental protection for new hydropower schemes has
been published by the Environment Agency.
Grid Connection
Information and guidance for connecting a renewable electric scheme will vary in the UK depending on the Distribution
Network Operator, for further information contact the Distribution Network Operator or visit their website.
Area
Company
Website
North
Scotland
SSE Power
www.ssepd.co.uk
Distribution
Central and
Southern
Scotland
SP Energy
Networks
www.spenergynetworks.co.uk
North East
England
Northern
Powergrid
www.northernpowergrid.com
North West
England
Electricity
North West
www.enwl.co.uk
Yorkshire
Northern
Powergrid
www.northernpowergrid.com
Merseyside,
Cheshire,
North
SP Energy
Wales and
Networks
North
Shropshire
www.spenergynetworks.co.uk
East
Midlands,
West
Midlands,
South
Wales &
South West
England
Western
Power
www.westernpower.co.uk
Distribution
Eastern
England
UK Power
Networks
Southern
England
SSE Power
www.ssepd.co.uk
Distribution
www.ukpowernetworks.co.uk
London
UK Power
Networks
South East
England
UK Power
Networks
Northern
Ireland
Northern
Ireland
Electricity
www.nie.co.uk
Planning Portal
Planning Portal Renewable and Low Carbon Energy
Technical Toolkit
Lighting
New Build
2.2.7 Lighting
NZEB Lighting (NBND)




Minimise artificial lighting energy demand by energy efficient lighting
design:
o Type and efficacy of bulbs used
o Fixtures, fittings & lighting arrangements
o LUX level requirements for varying space functions
Use lighting controls to minimise unnecessary use:
o Sensors
o Bi-level switches
o Timers
Maximise natural day-lighting:
o Building orientation
o correct sizing & positioning of windows
Use energy efficient light bulbs in all locations
o Maximum permitted LUX levels not to be exceeded by more than 5%
o Minimum permitted bulb efficacy is 65 Lumens /Watt
This section looks at energy efficient lighting systems in buildings other than dwellings such as office, commercial,
industrial, educational and leisure buildings. Lighting alone accounts for 14% of energy consumption across Europe,
therefore the impact of lighting is significant and can play a large part in reaching EU renewable and emissions targets.
Fig1. Europe Lighting By Night (Source: Giz Mag)
Lighting not only consumes energy itself, but it is important to recognise that heat gains from lighting leads can lead to
the need for artificial cooling, which itself can consume large amounts of energy. Therefore, energy efficient lighting
design can play a significant role in decreasing the energy consumption in a building, leading to up to 18% cost savings.
The EPBD (2010) states that, in terms of a Near Zero Energy Buildings:
N
Z
-E
B
A
f reducing energy
consumption as much as possible is one way of ensuring this. Therefore, reducing the energy requirement due to lighting
must play a part in a building being Near Zero Energy.
The overall Primary Energy Demand for various non-domestic buildings are set out in Section 2.2.1.1: NZEB Design
Approach. This varies from building type to building type, and therefore it is hard to give exact examples of lighting
energy demand requirements, as this depends on the size and use of the building. However, to reach NZEB status, the
overall primary energy demand for new build non-domestic buildings must be met, and Lighting must be taken into
consideration as part of these calculations.
Lighting Levels
Light is measured in lumens and LUX. Lumens is the flow of light from a source. The LUX is the amount of lumens per
square meter hitting a surface. Therefore, whatever the distance from the light source, the lumens remains the same as
the source emits the same amount of light. However, the LUX, or amount of light hitting a surface reduces the further
away from the source the surface is.
Fig2. The difference between lux and lumens (Source: Daylightcompany2009)
For non-domestic buildings, the illuminance, or LUX levels vary from building type to building type, and from space to
space, depending on the function of that space. For example, corridors and stock rooms do not need to be lit to the same
extent as an office building or classroom. The image below gives an indication of lighting levels for different non-domestic
settings.
Fig3. Lighting Levels For Different Non-Domestic Settings
The Chartered Institution of Building Services Engineers (CIBSE) has very detailed lighting guides for various different
types of buildings. For general information, CIBSE Guide A, Table 1.11 gives details on the recommended LUX values for
various activities and room usages.
Fig4. CIBSE Guide A: Table 1.11 (Source CIBSE)
Energy Efficiency
The efficacy of a bulb is the ratio between the bulbs output in lumens and the power it uses in watts. The higher the
efficacy, the greater the energy efficiency of the bulb. To gain the required LUX levels as outlined above, the highest
efficient bulbs should be used in all fittings. Efficacy of bulbs is measured in lumens per Watt, with standard bulbs having
the efficacy as shown in the image below.
Fig5. Light Output From Different Bulb Types (Source: Penn State College, Department of Energy & Mineral
Engineering)
Daylighting
In order to minimise the energy consumed by artificial lighting, the amount of natural light should be maximised.
Daylighting is the term for when natural light is used to illuminate a building. The position and size of windows is critical
to ensure maximum use of natural light.
Along with daylighting, energy efficient artificial lighting systems should be used to minimise energy consumption. There
are a number of guides and practice codes on lighting systems:
Carbon Trust Lighting Guide
BRSIA Illustrated Guide to Building Services
CIBSE Guide A: Section 1.8 & Section 6.4
CIBSE Guide F: Chapter 9
Lighting Design Tools
DIALux is a free programme for lighting design and planning. It can show the effect on energy consumption and
luminance of different lighting systems and bulb types. Therefore, the most energy efficient lighting system can be found,
whilst still achieving acceptable LUX values on the working surface. Simulate an existing building and then make changes,
such as paint the walls a lighter colour, change lighting fixtures, add lighting controls or add skylights to a room, and see
the effect this has on the LUX values within the room.
Other software that can be used to simulate the effect of lighting systems in a building include:
IES Virtual Environment dynamic simulation modelling programme
Lesodial - Daylight calculation software
When designing lighting, the main things to take into consideration are; Efficient Lighting systems, Lighting controls and
Daylighting. Further information is available on Lighting controls and Daylighting downloadable from the toolkit section of
the SustainCo website. Further details on Efficient Lighting systems can be found below.
Light Guide Series on Lightsource.com
The Lighting Association: Lighting Guides
Energy Saving Trust: Lighting
Trainenergy-iee.eu: Module 7.5 Lighting
Video Links:
Making the Switch: Promoting Energy Efficient Lighting Systems
Technical Toolkit
Energy Efficient Lighting
2.2.7.1
New Build
Energy Efficient Lighting Systems




design:
o Sensors
o Bi-level switches
o Timers
Energy efficient lighting systems should be incorporated into the design of a new building. The internal heat gains
associated with lighting should also be taken into account, in order to minimise energy consumption required for cooling.
The key items to take into account are:


Type of light bulbs (lamps)
Light Settings/fixtures


Field Arrangement
Light function/Use
Type of Bulbs
The term lamp is often used to mean light bulb. There are 5 main forms of artificial light, more information on each can
be found on the Lighting Industry Federation website:





Incandescent
LED
Discharge
Fluorescent
Induction
For NZEB standards, the minimum permitted efficacy of bulbs to be used should have an average starting efficacy of 65
Lumens/Watt. This effectively rules out the use of incandescent bulbs and mercury bulbs. This is in line with the 2009 EU
Regulation (EC) No 244/2009, which started the phase-out of inefficient, non-directional bulbs. The completion of this
phase-out was by September 2012. Further sections of the regulation deal with increasing the efficacy and functionality
of bulbs by 2016.



EC 244/2009
Frequently Asked Questions on EC 244/2009
European Commission Technical Briefing
Fig1. Lamp Efficacy (Source: Lighting Industry Federation)
Energy efficient light bulbs, such as Compact Fluorescent Light bulb (CFL), Light Emitting Diode (LED) and Metal Halide
bulbs should be used in all light fittings. Sust-it have produced a lighting guide and energy calculator that will show energy
and cost saving benefits of changing your light bulbs to more energy efficient bulbs.


Sust-it Lighting Guide
Sust-it Lighting Calculator
The Chartered Institution of Building Services Engineers (CIBSE) Guide A, lists different lamp types, giving their average
power density output in W/m2 for different achievable LUX values. Lower power density output means less internal heat
gain to the room. Less internal heat gains means less energy consumption required for cooling a room.
In terms of achieving NZEB standards in lighting, it is suggested the recommended LUX levels not be exceeded by more
than 5%. The recommended LUX levels are minimum requirements, but are more than adequate for most tasks being
completed in each space type. Specific cases may require higher LUX levels, and these can be dealt with on a case to case
basis.
Fig2. CIBSE Guide A table 6.4 (Source: CIBSE)
Light Settings/Fixtures
Light fittings and fixtures need to be taken into account in order to minimise internal heat gains whilst still achieving the
desired LUX levels on the working plane. Table 6.5 from CIBSE Guide A shows the different types of light fittings, and the
average percentage of energy distribution into a room. The lower the downward distribution, the lower the internal heat
gains to the room.
The main fitting types are:
 Louvre reduces glare
 Diffuser spreads light over a wide area
 Open
Fig4. Examples of fitting types
The main mounting types are:
 Suspended
 Recessed
 Surface mounted
Fig5. Examples of mounting types
Fig6. from CIBSE Guide A shows the different types of light fittings, and the average percentage of energy distribution
into a room. The lower the downward distribution, the lower the internal heat gains to the room.
Fig6. CIBSE Guide A Table 6.5 (Source: CIBSE)
Field Arrangement
The arrangement of lights can affect the LUX values reaching the working plane. The uniformity of the LUX levels depends
on the ratio of mounting height to space between lamps, which should be no more than 1.5. The distance of a light
source from the wall should also be equal to one half the distance between two adjacent light sources. Different ratios
are required for different functions within a room. The mounting height is the height between the bottom of the light
fixture and the working plane.
Fig9. Working Height (Source: Sylvania)
More information:
CIBSE Guide A: Section 1.8.3 1.8.5
Light Function
Lighting can be used for different functions. Understanding at design stage what type of light is needed and where, will
help minimise the use of artificial lighting once in operation:
 Ambient background lighting
 Task lighting to illuminate a particular area such as a kitchen work surface or a desk
 Accent/Decorative this type of lighting is used for aesthetic reasons rather than efficiency
Each space in a building has a different function, and therefore requires different levels of lighting. LUX level
requirements vary depending on the task being carried out or the use of a room. CIBSE Guide A, Table 1.11 gives
recommended LUX values for various activities and room usages. Design appropriate lighting by identifying the purpose
of areas within the building and what kind of tasks will be carried out in each space.
As previously mentioned, for NZEB standards it is suggested that the recommended LUX levels not be exceeded by more
than 5%.
BSRIA: Illustrated Guide to Building Services, P.37 Introduction to Lighting
Video Links:
Better Light with Less Energy
Building Other than Dwellings - New Build
Technical Toolkit
Lighting Controls
Building Other than Dwellings
New Build
2.2.7.2 Lighting Controls




design:
o Sensors
o Bi-level switches
o Timers
As discussed in Section 2.2.7.1: Energy Efficient Lighting (NBND), artificial lighting can use significant amounts of energy.
In terms of user behaviour, not switching lights off when leaving a room also contributes to the inefficiency of lighting
systems. The positioning of light switches plays an important role;
 ensure that switches are positioned in convenient locations (at entrances to rooms)
 avoid having switches behind doors, or awkward places, where access is impeded
Another way of ensuring lights are not left on unnecessarily is by using lighting controls. By using one or more lighting
control strategies, the energy consumption of lighting can be minimised. There are three main strategies that can be
used:
Another way of ensuring lights are not left on unnecessarily is by using lighting controls. By using one or more lighting
control strategies, the energy consumption of lighting can be minimised. There are three main strategies that can be
used:

Sensors:
o Occupancy sensors: switches that turn on a light when they sense motion, and turn off again after a set
period of time, giving a reliable way of ensuring lights are on only when required.
o Ambient Light Sensors: these sensors can establish the level of light in a room. The lights dim up and down
in response to background LUX levels, reducing output when background levels are sufficient

Bi-level switching: where each room is provided with two (or more) manual switches to control lights. In a typical
installation, one switch would control 1/3 of the ceiling lamps, with the second switch controlling the other 2/3 of
the ceiling lamps. Therefore, there are four possible lighting levels; Off, 1/3 on, 2/3 on and fully on Electrical
Contractor Magazine

Automated Time switches: a system that can be set up in order to turn off all lights on a particular floor or an
entire building, at certain times, such as during the day if the house in unoccupied, therefore once again ensuring
no unnecessary waste in energy consumption.
Fig.1 Daylight Sensors (Source: Power Systems Design)
Building Management Systems (BMS) can be used to integrate and control all appliances and electrical systems, including
lighting, in a building. They can then be controlled remotely by computer. The benefit of this is that heating, lighting,
pumps, motors and electronic appliances can be switched on and off from a remote location, saving energy by having
greater control of the electrical system.
It is critical to zone each area for use and function, so that different systems can be used to effectively monitor and
control each space in a building. For example zoning an office block to distinguish between offices, corridor spaces,
canteen, toilets, atrium and stairwell will allow for different levels of lighting to be set, and different controls to be used.
A BMS system can then help with correct monitoring to ensure the most efficient settings have been applied, and that
they are working correctly.
For more information on automated systems, see the following links:
 Building Management Systems
More Information
DiLouie, C. (2008) Lighting Controls Handbook. Fairmount Press Inc, Lilburn, GA 30047
Carbon Trust Lighting Controls
Lighting Industry Federation: Lighting Controls Guide
Video Links:
Smart Buildings
Technical Toolkit
Daylighting
2.2.7.3
New Build
Daylighting




design:
o Sensors
o Bi-level switches
o Timers
In order to minimise the energy spent on artificial lighting, the amount of natural light should be maximised. Daylighting
is the term for when natural light is used to illuminate a building. The position and size of windows is critical to ensure
maximum use of natural light.
Orientation of a building should play a role in the natural daylight design. Similar to a domestic setting, spaces which are
used more in the morning should face north, with spaces used primarily in the afternoon facing south. However, with a
non-domestic building, this is not as easy due to, in general, spaces being used throughout the day (or night). For
example, classrooms and offices used for the same purpose for 8-10 hours a day, 8am-6pm.
The effects of glare and internal heat gains must also be taken into account when designing for natural daylight. Shading
can be used to reduce both these effects on a space, and is discussed in more detail in Section 2.2.2.4: Windows &
Doors (NBND).
For a building to be completely lit by daylight, there are limits on its overall plan depth. If a room is lit by windows on
one wall only, the depth of the room (L) should not exceed the limiting value, given by:
Where:
W = Room Width
HW = Window head height above floor level
Rb = Average reflectance of surfaces in the rear half of the room (away from the window)
If L exceeds this value, the rear half of the room will tend to look gloomy and supplementary electric lighting will be
requires.
The Daylight Factor gives an indication of the amount of natural light contributing to lighting a room. It is the ratio of the
illuminance at a particular point inside a building to the unobstructed illuminance outside the building.
The Daylight Factor is calculated using the following equation. The values for Diffuse Transmission, maintenance factor
and weighted average reflectance can be found in Tables 1.12 1.14 in CIBSE Guide A.
Where:
DF = Daylight Factor
T = Diffuse transmittance of glazing (including effects of dirt)
AW = Area of glazing
= Vertical angle subtended by sky visible from centre of window
M = Maintenance factor
A = Total area of internal surfaces (m2)
Ra = Area weighted average reflectance of internal surfaces
The value of the Daylight Factor (DF) gives an indication as to whether sufficient daylight is available:
DF is > 5% = room is sufficiently lit by daylight
2% < DF > 5% = some artificial lighting is required
DF < 2% = artificial lighting is required most of the time
The equation can also be manipulated to calculate the area of window required to achieve a certain Daylight Factor.
Further information on daylight calculations can be found:
Harvard - Daylighting Rules of Thumb
THERMIE - Daylighting in Buildings
Lesodial - Daylight calculation software
However, it is unlikely that a building will be designed in such a way as to ensure daylighting reaches all parts of a space.
As can be seen in the image below, this office has large amounts of glazing on one wall, allowing for some of the office
space to be light by natural daylight. However the rear of the office, to the left of the image, is dark.
As discussed in Section 2.2.7.2: Lighting Controls (NBND), it is important to zone and control light switches with
sensors. Therefore to ensure that correct LUX levels are met throughout the office space, sensors can be used to turn on
lights at the rear of the office, while keeping them off a the front, where the lighting levels are sufficient due to the
natural daylight.
Fig1. Daylighting In An Office (Source: Life at HOK)
Rooflights
Rooflights can also be used to supplement the amount of daylight entering a room. Rooflights allow light to be
introduced to parts of a building that would otherwise be inaccessible to natural daylight. The ratio of spacing between
rooflights and height above the working plane affects the uniformity of the illuminance on the working plane, and must
be designed carefully, similar to artificial lighting arrangement design, as discussed in Section 2.2.7.1: Energy Efficient
Lighting (NBND).
The use of rooflights plays a larger role for non-domestic buildings, due to the shape and size of the building types in
comparison to domestic dwellings. For example, an office block, industrial building or educational facility may be much
larger than a domestic dwelling, with rooms set in the middle of the building, away from building envelope where
glazing is used to allow daylight in. The image below shows how the use of rooflights down the centre of the building
can allow natural light into sections of a building where otherwise daylight would not reach.
Fig2. Rooflights (Source: Brett Martin)
ECEEE - Best Practice for Designing Skylight
Energy Design Guidelines - Skylighting Designs
US Department of Energy - Skylight Design Considerations
Consumer Energy Centre - Skylights

Final New Build BOTD

Transcription

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