New Build Dwellings, once they are built: The EPC

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All new dwellings must have an assessment of energy performance (SAP), environmental impact (EI) and building regulations compliance undertaken at the design stage of the build, prior to works commencement. Once the dwelling is built, that assessment is revisited, with an as-built version required on completion and used to produce the Energy Performance Certificate or EPC for short…

An Energy Performance Certificate (EPC) is required for properties when newly constructed, sold or let. This will also apply if a building is converted into fewer or more units and changes are made to the heating, hot water provision or air conditioning/ventilation services.

It is the responsibility of the builder or developer to have an EPC produced when a new home is constructed and physically completed. The Building Control Body (BCB) will not sign-off on completion (usually), without having first received a notice which includes an as-built energy rating calculation to show that the completed dwelling complies with the building regulations, with a copy of the EPC supplied to the owner of the building, with confirmation to the BCB that it has been done.

New Build domestic EPC’s are produced following the Standard Assessment Procedure (SAP) methodology by qualified and accredited On Construction Domestic Energy Assessors (referred to variously as DOCEA’s or OCDEA’s, or OCEA’s).

An EPC can’t be produced from nothing – a SAP assessment sits at the heart of each one and needs to be updated to reflect what has actually been built.

OCDEAs produce EPC’s from updated design stage SAP calculations that have been updated to reflect what has actually been built, with any assumptions and anything that has changed during a build, being updated so that the calculation more closely reflects the reality. The calculations are updated based on a range of factors, including:

  • Postal address and correct orientation and location of the completed dwelling
  • Updated confirmed building fabric elements and junction information
  • Actual installed heating and hot water systems and their controls
  • Actual installed ventilation and tested air tightness information
  • Any additional energy efficiency affecting technologies installed
  • Anything else that’s changed from the design stage!

At this stage, for an assessor it’s all about the evidence gathering and confirmations, or necessary amendments needed to update the calculations; making sure that the calculations are accurate and if audited, the accreditation scheme can check that all of the inputs have a firm basis and are correctly entered.

Ideally, the builder should stay in touch with the assesor right through the build, so that any potential changes can be checked and incorporated into the calculations, to avoid non-compliance at the end of the build and to ensure that poorer than initially proposed energy efficiency or environmental impact ratings are avoided.

Without good communication, a builder can suddenly find out (once it’s built) that their dwelling fails to comply, or has poor ratings, due to a decision to change the fabric to a poorer specification, or to change their heating systems, to those less efficient, or using a different more costly fuel, without first checking the effects of that decision. This can result in last minute expensive bolt-on’s being needed to be installed in order to get BCB to sign off on non-compliant builds.

The As-built energy assessment is used to show that the completed property complies with regulatory requirements and is used to produce the EPC for the finished dwelling, with the EPC lodged via the accreditation scheme to  the body who administers the Domestic Energy Performance Certificate Register on behalf of the Government (Landmark for England and Wales) for inclusion on the national register.  Separate national registers are maintained for Scotland via the EST and for Northern Ireland (again via Landmark in that case).

Accredited assessors can be searched for via each of the EPC registers linked to above, although unlike with Domestic Energy Assessors, proximity to the site isn’t necessarily so important as the inputs are based on plans and advised specifications.  Some assessors do visit sites as part of other service offerings (e.g. air tightness testing), but it is not the norm.

All OCDEAs must be accredited and be members of an approved scheme to be able to issue EPCs. To become accredited and join a scheme, they must demonstrate evidence of their qualification and competence to meet the National Occupational Standards. Once accredited, OCDEAs are regularly audited and monitored by their accreditation scheme.

An EPC is not a guide as to how much your energy bills will actually be, although it does include ‘typical’ running costs for heating, hot water and lighting;

The running cost estimates on a domestic EPC are only a guide, based on standardised occupancy and heating patterns and don’t actually cover everything on your bill.

The actual energy use and costs will include cooking and appliances use and will be based on how you actually live in a house, how often you heat it and how much you do. In addition it is based on how much hot water is actually used by real people and on real fuel costs which tend to rise more often than fall, rather than the previous years averages that the EPC calculations use.

EPC’s inform builders, potential buyers, owners and tenants about the comparative energy efficiency of a home, the higher the rating, the more energy efficient it should be and the lower the costs to run.

The EPC also includes some indication of how the dwelling could be improved. For new build EPC’s, typically these potential improvements are minimal, as the best time to improve the energy performance is when it’s constructed and minimum standards dictate that the building will meet a reasonable level of performance.

The best time to minimise demand and achieve a more highly rated, more efficient dwelling is when the construction is designed and built, so it is then that the fabric design should be pushed and future running costs considered and reduced. No-one is likely to jump into adopting recommendations to improve a dwelling that has only just been built. If you think it through, the recomendations should appear at the design stage…

Kingspan Insulation’s technical department offers a SAP assessment service, undertaken by accredited On Construction Domestic Energy Assessors, which includes analysis of all of the information provided by a customer for energy assessments for developments and guides the customer through the various relevant requirements, offering advice as part of the service where a specification may fall short of compliance. More details are available on the SAP pages of our website.


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Jon Ducker is a qualified energy assessor working for Kingspan Insulation Ltd. He has an extensive knowledge of energy efficiency, renewable energy systems and sustainability in buildings with an expert knowledge of the relevant sections of buildings regulations and standards and their interactions with SAP. He provides authoritative advice regarding energy assessments for a wide range of public and private sector clients.

0 comments on “New Build Dwellings, once they are built: The EPC
  1. Hi, I have a couple of questions regarding EPC’s

    1. What assumptions are made if ‘as built’ is selected for roof insulation?

    2. What are the Scheme Operational Requirements on Accreditation Bodies?



    • Hi Mike

      Thanks for your questions. One of our accredited energy assessors, Hannah, has provided the following answers:

      1. For new build dwellings no assumptions are made at ‘as-built’ stage. The whole specification including wall, roof and floor build up has to be provided by the contractor / designer and signed off to confirm the project has been built to that specification. If products such as roof insulation have been switched out for another insulation type, thickness or manufacturer, then this has to be updated in the calculation software before the ‘as-built’ SAP assessment and EPC are produced. Changes to the specification may affect not only the U-value but could also impact on the thermal bridging (if manufacturer specific Psi values have been used) and, as a result of both, could impact on compliance.
      For existing dwellings that require an EPC when they are sold / rented, if the assessor cannot easily find or confirm the existence of the roof insulation then they have to assume that no insulation exists for the purposes of the assessment.

      2. All energy assessors must be accredited with a registered body which is approved by DCLG to operate an accreditation scheme for energy assessors (eg Stroma, ECMK, Elmhurst, NHER, etc). The accreditation bodies have scheme operational requirements on their websites. The requirements include such things as:
      a. Members are fit and proper persons to undertake energy assessments
      b. Members operate within a code of conduct
      c. Members are qualified to undertake energy assessments
      d. Members have suitable indemnity cover
      e. Members use operation procedure that ensure consistency and accuracy of energy assessments

      This list is not exhaustive but gives an idea of the things covered by the accreditation bodies. All of our energy assessors are accredited with a DCLG approved body. Accredited assessors can be searched on the following site:

      Hope this helps.

    • Hi Joseph,

      The assessor is subject to a code of conduct (which they must sign up to) from their accreditation scheme, which includes a section on conflicts of interest and must disclose any personal or business relationship with the client. The energy assessment software we use requires the assessor to select an appropriate declaration for each assessment in order to be able to proceed with the assessment.The accreditation scheme codes of conduct are available online from a quick search if you’d like more information.

      Many thanks,
      Jon Ducker

  2. Brought new build 5 years ago and now selling but do not seem to have ever got EPC from the building firm.

    • Have a look on the EPC register to see if your property has had one produced. You can searching by address here.

      If it has been produced it will be available to download using the search function. You may save and print a copy of an Energy Performance Certificate you obtain from this register as long as you do so for your own purposes.

      If the report comes back negative or ‘false’, then an EPC was not produced.

      Energy Performance Certificates (EPCs) are needed whenever a property is built, sold or rented.

      Hope this helps,

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