How is the building area calculated?

Floor areas for energy assessments are based upon Gross Internal Area (GIA) as defined in the current RICS Code of Measuring Practice.  Further information can be obtained here.

In order to complete a Display Energy Certificate, the GIA of the building must be accurately determined.  The energy assessor is responsible for verifying any value provided and for ensuring that it is accurate.  The default fallback position is that the energy assessor will be required to measure the building to determine the GIA.

However, it is recognised that the buildings requiring DECs are often large and complex.  As such, it is likely that other professionals are involved in building management and a GIA for the building may be available from other means.  This can avoid the lengthy and costly process of the energy assessor measuring the entire building e.g. a large college or acute hospital.  Therefore, DEC assessors are authorised to accept the following sources of information providing they take appropriate sample site measurements to verify the figures used are reasonable.  The acceptable secondary sources are:

  1. Measurements from scaled drawings: – This method can be used where professionally produced scaled plans are available for the building.  It is most useful when measurement layers have been turned on.  Particular care must be taken to ensure that measurements shown are Gross and not Net of internal walls etc.
  2. Areas from a formal Asset Register or similar: – This is often the simplest method where a suitable document exists but the energy assessor must be able to demonstrate that this is a formal document that has been professionally produced.  Documents in electronic format are acceptable.  Particular care must be taken to ensure the figures used are clearly identifiable, accurate, current and Gross not Net.  It is not unusual for these registers not to be updated to reflect building changes or for inaccurate or Net figures to be input in error.
  3. Information from an Architect or Surveyor who has reason to know: – Where an Architect or Surveyor who is registered with an appropriate professional body has undertaken work relating to the building they may have established the GIA.  This value can be used with appropriate supporting evidence.  This is also the justification used to accept a GIA printed on professionally produced scaled drawings of a building.

Uniquely for DEC’s, it is sometimes acceptable to use alternative measures of floor areas for some specific types of building.  However, these exceptions are very limited and the software used to produce the DEC converts these values to GIA before calculating the building rating.  The conversion is very conservative and so the rating will nearly always be considerably worse if these values are used that if the GIA is used directly.  Additionally, the GIA is normally available when a suitable source of these values is provided and so using them is not advisable.

Do I need an Advisory Report completing as well?

Advisory Reports (AR) provide information about the way energy is managed and used within a building.  They provide recommendations for improving energy efficiency which can help reduce energy bills if successfully implemented.  Even where they are not required, it is often beneficial to have the AR for a building completed or updated.  This is particularly true when the energy assessor has to complete a site visit to issue the DEC as the additional work for the assessor is limited and this should be reflected in the assessment price.

In England & Wales, a valid Advisory Report is legally required to be in place before a DEC is issued.  In reality, they are usually both added to the national register at the same time when required but they can be completed separately.  The Advisory Report must be for the same building and occupier as the DEC so they should both be accessible under the same entry on the register.  It is the responsibility of the energy assessor to check the register to ensure that the AR is in place before lodging the DEC.

In Scotland, Advisory Reports are voluntary but will be required if it is intended to use the DEC within the Energy Saving Opportunities Scheme (ESOS).

What is a “Building” for DEC purposes?

For the purposes of Display Energy Certificates, a building must have a roof, walls and use energy to condition the indoor climate.  This is the case where the building has any of the following fixed services:

  • Heating;
  • Cooling; and/or
  • Mechanical ventilation (this means the supply of fresh air and extraction of stale air – not just an extraction fan).

It is not uncommon for a site to have multiple buildings or a large building built is multiple phases.  If two or more buildings on the same site are linked by a fully enclosed structure consisting of a roof and walls, even if the link is not itself conditioned, then the combined buildings can be considered a single building for DEC purposes providing they have not been designed or altered to be used separately (usually by separate occupiers).  This approach is particularly sensible when the different parts are serviced by the same common systems and where sufficient sub-metering is not in place.  However, they may still be treated separately which can be useful in identifying energy efficiency improvements and monitoring energy usage.

NB: Since February 2009 site based DECs and ARs no longer meet the requirements of the legislation.  All qualifying buildings on a site must now have their own Display Energy Certificate and Advisory Report.

Are Listed Buildings exempt?

There is a lot of confusion about exemptions relating to listed buildings and buildings within a formally designated conservation area.  Firstly, the exemptions that exist appear to vary between administrations in the UK and are different for different forms of assessment.  Secondly, the supporting guidance, particularly in England & Wales, is regularly updated and can appear inconsistent or incomprehensible.

Air Conditioning Energy Assessments & Display Energy Certificates

Dealing first with these two assessments, the need for compliance is not affected by the historic nature or otherwise of the building.  As such, no exemptions from the requirements for these assessments exist specifically for buildings that are listed or in formally designated conservation areas.

Listed buildings and those in formally designated conservation areas are treated as any other building is treated and require Air Conditioning Energy Assessments (ACEAs) and Display Energy Certificates (DECs) if they meet the other qualifying criteria.

Buildings in Scotland

The Scottish Government has not attempted to exempt listed buildings or buildings in formally designated conservation areas from their regulations for energy efficiency.  Instead, they have taken an approach where an assessor is required to consider the impact of improvement measures and their appropriateness for the specific building in question.   As such, no exemptions from the requirement for an Energy Performance Certificate exist specifically for buildings that are listed or in formally designated conservation areas. [Click here to see guidance]

Listed buildings and those in formally designated conservation areas in Scotland require Energy Performance Certificates (EPCs) and Section 63 Action Plans if they meet the other qualifying criteria.

Buildings in England & Wales

Put politely, the situation for buildings in England and Wales is about as clear as mud.  The wording in the current regulations is taken directly from the European Directive and says “buildings officially protected as part of a designated environment or because of their special architectural or historical merit, in so far as compliance with certain minimum energy performance requirements would unacceptably alter their character or appearance.”

When these regulations were enacted on 9th January 2013, it was generally accepted that listed buildings were exempt from the requirement for an EPC for sale or let although it was acknowledged that they would still require an EPC in other circumstances (e.g. Green Deal).  This belief was re-enforced by guidance published by Historic England which includes the statement “An Energy Performance Certificate (EPC) is a legal requirement when building, selling or renting a property. However, there are exemptions for certain types of building and since January 2013 listed buildings have been exempted from the need to have an EPC.”  However, Historic England’s Terms and Conditions include the usual disclaimers regarding their interpretation of the law in that the position stated was just their interpretation and that they accept no liability for its accuracy.  In the absence of enforcement action or legal precedents being set, much discussion has continued both in and out of the legal community with differing interpretations resulting.

Moving forward to the latest guidance to come from The Department of Business, Energy and Industrial Strategy, the UK Government Department which now has responsibility for EPCs.  Issued in February 2017, this update is contained within the guidance for landlords and enforcement authorities on the minimum level of energy efficiency required to let non-domestic property under the Energy Efficiency (Private Rented Property) (England and Wales) Regulations 2015.  The advice, published in Chapter 1 on page 19 is shown below:

“There is a common misunderstanding relating to listed buildings and whether they are exempt from the requirement to obtain an EPC. Listed properties, and buildings within a conservation area, will not necessarily be exempt from the requirement to have a valid EPC and it will be up to the owner of a listed building to understand whether or not their property is required to have an EPC. Where a listed privately rented non-domestic property, or a property within a conservation area, is required to have an EPC, that property will be within scope of the minimum energy efficiency standards.

“As noted at 1.3.3 above, an EPC is not currently required for a listed property or building within a conservation area when it is sold or rented in so far as compliance with minimum energy performance requirements would unacceptably alter its character or appearance. Examples of energy performance measures which may alter character or appearance (or as a minimum are likely to require local authority planning permission to install on a listed building) include external solid wall insulation, replacement glazing, solar panels, or an external wall mounted air source heat pump. Where character or appearance would not be altered by compliance with energy performance requirements, an EPC may be legally required.

“If an owner or occupier of a listed building is unsure about whether their particular property is or is not required to have an EPC, appropriate advice should be sought at the earliest opportunity.”

Exactly the same information is contained within the equivalent publication for domestic properties which has been published more recently in October 2017.  Changes in other guidance documents issued by MHCLG (formerly DCLG) and BEIS have also been made to reflect this.  However, whilst they tend to reduce the previously special status given to listed buildings to a par with other designations including Conservation Areas, National Parks, Scheduled Monuments and protected parks and gardens, they do little to clarify exactly how far an exemption applies.

This guidance would seem to suggest that the UK Government believes the exemption for listed buildings is much more restricted than had previously become accepted.  Indeed, it would appear to be more compatible with the Scottish Government’s interpretation that the exemption is solely from making improvements that would unacceptably alter the protected building’s character or appearance and not from the entirety of the process.  Similarly, it would appear to reflect an expectation that reasonable improvements, particularly where these would improve the energy efficiency of a building whose performance is currently very poor, should be carried out.

This is not without merit or logic. At the current time, an EPC in itself does not mandate that any works actually be carried out. The recommendations are just that, recommendations. Therefore a view could be formed that having an EPC can never unacceptably alter the character or appearance of the building. As such it could be argued no building can claim exemption from having an EPC on these grounds alone. Additionally, the current requirements under the MEES include provision for exemptions from making specific improvements where required third party consent cannot be obtained. Hence, if Listed Building Consent cannot be obtained from the relevant authorities no unacceptable alteration to the character or appearance of the building is required and so again, there is no need to apply this exemption from having an EPC.

Many councils provide guidance on improving historic buildings with Westminster City Council providing some of the most extensive and practicable advice we have found. This includes a document titled “Energy Efficiency in Conservation Areas” which discusses improvements that can be made without damaging historic structures.

It may have taken some time but even Historic England have now updated their guidance to emphasise the limited nature of the exemption for both Listed Buildings and those in designated Conservation Areas. (NB: We cannot accept responsibility for the actual content of third party websites and it would appear that even this revised guidance contains some technical errors relating to EPCs).  They also provide a wealth of information for those wishing to improve historic buildings without damaging their character and appearance.  Indeed, they acknowledge that ensuring a building remains useful and occupied is often the best way of protecting it for the future.  Additionally, some energy improvement measures can also improve fire safety and resilience in historic buildings.  It should be remembered that it was never the intent of the protection schemes to freeze buildings in time but instead to ensure that they are managed with appropriate sympathy and conserved for the future.

The background to this issue is also explored in an article by The Residential Landlords Association.  They make the following observation in relation to the exemption of Listed Buildings from EPCs:

“So in reality, in terms of an EPC, the caveat is meaningless. Therefore, a landlord cannot know if an EPC is needed before they have an EPC for the property”

This article continues to draw the following overall conclusion:

“Regrettably, we simply do not know the answer to whether or not an EPC is required for a listed building; nor whether landlords who have rented out listed buildings will have to comply with Minimum Energy Efficiency Standards (subject to any other available exemption, e.g. limiting the amount they have to spend); or whether you need an EPC for a listed building in order to be able to rely on regaining possession under Section 21 of the Housing Act 1988. What is clear is that if you have no EPC then you do not have to comply with Minimum Energy Efficiency Standards from 2018 onwards. You could be liable for a penalty for not having an EPC and equally you might not be able to get possession back relying on Section 21. This is a wholly unsatisfactory state of affairs which needs to be addressed by the Government.”

Interestingly, at a recent industry conference (Spring 2018), representatives of both MHCLG and BEIS confirmed that they believed Listed Buildings should have EPCs completed and that recommendations should be implemented wherever possible but with appropriate sympathy to the building as a whole.  They were unaware of the conflicting guidance from Historic England which they accepted may be the source of a lot of the current confusion and undertook to attempt to ensure that Historic England updated their guidance to more accurately reflect the limitations of any exemptions which may be available.

Unfortunately, as energy assessors, we are not in a position to provide legal advice but present this information to help you form your own opinion.  However, we would point out that there is currently nothing to stop an EPC being completed on a voluntary basis even when one is not required by law.  This may have its own implications and so building owners and occupiers should seek their own legal advice but voluntary compliance may provide a suitable solution.

Some listed buildings in England & Wales may be exempt from some or all of the Energy Performance Certificate (EPC) and Minimum Energy Efficiency Standards (MEES) requirements.  However, specific legal advice should be sought on a case by case basis.  It is unlikely that an exemption can be demonstrated without first having an EPC completed to confirm the recommendations proposed.

Buildings within formally designated conservation areas are less likely to be subject to exemptions.

What is a “Public Authority”? Is my charity/community group a public authority?

Unfortunately the current regulations in England & Wales provide no clear definition of the term “Public Authority”.  However, the regulations were intended to include central and local government, schools, colleges, academies, free schools, universities, hospitals, NHS funded centres and surgeries, libraries, publicly funded museums, emergency services, social services, publicly funded sports and leisure facilities and most other civic buildings.  As such, with the current format of service provision by charities, not-for-profits, community groups, agencies and arm’s length organisations, it is not correct just to assume the term is restricted to government departments and council facilities.

In the absence of a clear definition, it has become commonly accepted that the meaning of “public authority” in The Energy Performance of Buildings Directive (England & Wales) 2012 regulations is the same as the term “contracting authority” as defined in 2(1) of The Public Contracts Regulations 2015.  Additionally, a similar list of “public authorities” can be found in The Freedom of Information Act 2000.  This definition is further reflected in The Energy Savings Opportunity Scheme Regulations 2014 which ensures organisations are potentially subject to either mandatory Display Energy Certificates or Energy Savings Opportunities Scheme (ESOS) assessments but should not be simultaneously subject to both set of regulations.

The Public Contract Regulations 2015 state:

“contracting authorities” means the State, regional or local authorities, bodies governed by public law or associations formed by one or more such authorities or one or more such bodies governed by public law, and includes central government authorities, but does not include Her Majesty in her private capacity;

“bodies governed by public law” means bodies that have all of the following characteristics:—
(a)they are established for the specific purpose of meeting needs in the general interest, not having an industrial or commercial character;
(b)they have legal personality; and
(c)they have any of the following characteristics:—

(i)they are financed, for the most part, by the State, regional or local authorities, or by other bodies governed by public law;
(ii)they are subject to management supervision by those authorities or bodies; or
(iii)they have an administrative, managerial or supervisory board, more than half of whose members are appointed by the State, regional or local authorities, or by other bodies governed by public law;

Public Authority – Self Determination Questionnaire

If, as an organisation, you are unsure as to whether or not you are a “public authority” you should seek you own legal advice.  When considering if your not-for-profit or charity is subject to these regulations the key would normally be in deciding if you are a body “governed by public law”.  The following steps may help your trustees/directors to decide:

  1. Are you listed in Schedule 1 of The Public Contracts Regulations 2015 (click to view) or Schedule 1 of The Freedom of Information Act 2000 (click to view), a regional authority or a local authority (county, borough, district, town, parish councils etc.)?  If your organisation is one of these then you are a “public authority” and will require DECs on the premises you occupy if the floor area and public visitation requirements are also met.  If you are not listed you should continue to step 2 to see if you are subject to the regulations through the additional criteria.
  2. Do you have a legal personality for the purposes of the regulations?  In effect, are you a legal body other than an individual?  Typical examples could include limited companies (including charitable companies), limited liability partnerships (LLP), community interest companies (CIC), charitable incorporated organisations (CIO), co-operative societies (Co-op), community benefit societies (BenCom) and financial mutuals.  If your organisation is any of these you may be a “public authority” and should continue to step 3.  If not, you probably have no legal personality in this sense and so are not subject to mandatory DECs.
  3. Is your organisation established for the specific purpose of meeting needs in the general interest, not having an industrial or commercial character?  A traditional business exists to make wealth (money) for distribution to its owners, investors and shareholders.  In other words, it has industrial or commercial character and would not be considered a “public authority” hence you are not subject to mandatory DECs.  In contrast, public bodies in this sense exist to meet the general needs of society or of communities.  They often provide services like health, social care, education, child care and recreation etc on a not-for-profit basis.  They typically use any profits they make from business activities to reinvest in the provision of these services.  They may also have a legal “asset lock” preventing the distribution of any profits or assets to members or shareholders.  If you are a public body then you may be a “public authority” and should continue to step 4.
  4. Does the majority of your finance come from the State, regional or local authorities or other bodies governed by public law?  If the majority of your organisation’s funding comes from the government, regional authorities, local councils or other public bodies (likely to include grants from charities etc) then you are a “public authority” and will require DECs on the premises you occupy if the floor area and public visitation requirements are also met.  If not, continue to step 5.
  5. Are you subject to management supervision from the State (including central government departments), regional or local authorities or other bodies governed by public law?  A simple way of determining this is to consider if you are free to run your organisation as you wish or whether you have to account for decisions that are made or actions taken to another organisation.  For example, most organisations receiving public money have to report upon the activities funded directly or indirectly back to the funding organisation, i.e. they are subject to supervision to ensure the money is spent as intended.  Registered Charities are subject to the supervision of the Charity Commission which is part of the State.  Similarly NHS practices are subject to supervision from the Department of Health through NHS Trusts and schools, colleges and academies are subject to supervision by the Department of Education through OfSTED.  If you are subject to management supervision then you are a “public authority” and will require DECs on the premises you occupy if the floor area and public visitation requirements are also met.  If not, continue to step 6.  [NB: Educational establishments should remember that students are considered to be members of the public under these regulations.]
  6. Do you have an administrative, managerial or supervisory board with more than half its members appointed by the State (including central government departments), regional or local authorities or other bodies governed by public law?  If your organisation does then it is a “public authority” and will require DECs on the premises it occupies if the floor area and public visitation requirements are also met.  If not, you are probably not a “public authority” and so will not require mandatory DECs on the premises you occupy.  However, “public authorities” are exempted from ESOS and so you may be subject to the requirements of the Energy Savings Opportunities Scheme.

What information will the DEC Assessor require? How can I keep costs down?

Your assessor will require the following information about your building to complete the assessment:

  • The name and address of the building including the postcode;

  • Some details about how your building is used and maintained;

  • The Total Useable Floor Area (TUFA) or Gross Internal Area (GIA) of the building;

  • Metered energy consumption (gas & electricity) for a 12 month period*;

  • Measurement of any other energy consumption e.g. oil & solid fuel;

  • The published opening hours of the building;

  • Details relating to on-site renewables and low or zero carbon technologies;

  • Details of any surplus energy exported to the grid.

During the assessment process the assessor will also visit the building. During this visit the assessor will need to visit plant rooms, meters, air conditioning systems and occupied areas to gather evidence for their report. They will also take photographs of your building and the systems installed within it. These photos are only to show features of the building fabric, its layout and how energy is being used so the assessor will avoid including people or sensitive information wherever possible.

All information obtained will be securely stored and only used for the purpose of producing your Display Energy Certificate and Advisory Report. If you have any concerns please discuss these with the assessor who can also let you review photographs taken if required so that you can be reassured these are appropriate. It may also help to arrange for the assessor to visit the building outside normal opening hours when less people will be about.

* This information may come from your own meter readings or energy bills. The information supplied does not have to cover exactly 365 days but information for all fuels needs to cover more or less the same period. Further details can be obtained from the assessor if required.

Keeping Costs Down

Prior to conducting a site visit the assessor will request certain information about the building. You can help reduce the time taken, hence reducing the cost of the assessment, by ensuring the information you provide is accurate and that all the requested information is provided promptly.

In particular, providing the assessor with an acceptable method of confirming the floor area and layout of the building will save the assessor having to measure the building. Accurate scaled floor plans produced by an architect or surveyor annotated with the Gross Internal Area (GIA) are ideal.

Accurate and comprehensive energy data is also very important for an accurate assessment. Many organisations already report annual energy consumption over specific periods. If you have already collated this information for a particular period please discuss how this can be utilised to reduce the duplication of data collection with your assessor. Your assessor can also advise on easy methods of accurately collecting the required information for future assessments.

How long is a Display Energy Certificate and Advisory Report valid?

England, Wales & Northern Ireland

The validity of a Display Energy Certificate (DEC) and Advisory Report (AR) depend upon the floor area of the building.  For buildings with a floor area greater than 1000m2, the DEC is currently valid for one year and the AR for up to seven years.

For buildings with a floor area greater than 250m2 but less than 1000m2, both the DEC and AR are currently valid for up to ten years.

However, significant changes to the occupation of the building or its floor area may require a new DEC or AR.  As the DEC relates to the occupier not the building, a change in occupier will require a new DEC.


In Scotland DECs are required annually for building deferring their Section 63 Action Plans and so all DECs are valid for one year.

There is no requirement to have an AR in Scotland and so a validity period is not relevant in this context.

What constitutes “frequently visited by the public”?

The key here is the frequency, not the number of visitors.  A small number of people visiting the building weekly would meet this definition. However, a large number visiting once a year (e.g. for an open day) would not.

However, it is important to note that visitors only have to visit part of the building.  They do not need to have access to all of it to be considered a visitor.  Someone visiting a reception area, however small, would be considered to be visiting the building.

Employees, residents of the building, suppliers, contractors or specially invited people (e.g. job applicants invited for interview) are not considered to be members of the public. However, students at an institution are considered to be members of the public.  Equally, residents in a complex visiting other buildings on the site may be considered to be members of the public.  In a healthcare setting, patients are considered to be members of the public.

Do I have to follow the AR recommendations?

Put simply, no.

When the Advisory Report is issued it will include some recommendations to help you save energy, reduce your energy costs and reduce your CO2 emissions.  It will also give you an idea of the typical cost of making these improvements and the reduction in emissions that is likely to be associated with each improvement.

However, these improvements are not mandatory and it is up to you to decide whether or not you want to make them.  You will want to consider how quickly the savings will pay for the improvements and what impact the changes will have on your organisation and property.

In the future some buildings with very low ratings may have to have improvements carried out to improve their overall rating.  Even so, it will be up to the owners to decide which improvements they wish to make.  This is already the case in Scotland where some buildings now require a Section 63 Action Plan.

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