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New Build EPCs and Site Visit Requirements for NDEAs

Charlotte Lancaster

Last Update 7 days ago

 

Non-domestic EPC assessments are not always carried out on existing, occupied buildings.


An assessor may also be instructed to produce an EPC for:

  • a newly constructed commercial building;
  • a shell-and-core building;
  • a newly completed extension;
  • a building that has undergone a major change;
  • or a building where a previously unconditioned space has become conditioned.

These situations require a slightly different approach from a standard existing-building assessment.


For an existing building, the assessor will normally visit the property, inspect its fabric and services, take photographs, record measurements and build the assessment from what is physically present.


For a genuine new-build assessment, much of the evidence can instead come from the design team, developer and Building Control documentation.


Understanding the distinction is important because it determines:

  • whether a site visit is required;
  • what evidence can be relied upon;
  • how the building should be classified;
  • and which Building Regulations requirements apply.


    What is a new-build non-domestic EPC?

    The simplest example is a completely new commercial building constructed from the ground up.

    For example:

    A new two-storey office block is constructed on a previously vacant site.

    This is clearly a newly constructed building.


    Once construction is physically complete, the person responsible for the construction must provide the building owner with an EPC and recommendation report and notify Building Control that this has been done. Building Control will not issue its completion certificate until it is satisfied that this requirement has been met.


    However, an NDEA may encounter less obvious situations which are treated in a similar way.


    Examples may include:

    • first fit-out of a shell-and-core unit;
    • a substantial extension;
    • a building becoming conditioned for the first time;
    • or certain relocated modular buildings.
     

    New-build assessments are Level 4

    Newly constructed buildings are treated as Level 4 complexity for non-domestic energy assessment purposes.

    This means that an assessor completing the assessment must hold the appropriate Level 4 qualification and accreditation.


    Level 3 assessors may assess many straightforward existing commercial buildings, but new-build work falls outside the Level 3 scope.


    This is important for learners because the software used may look familiar, but the complexity classification and evidence requirements are different.

    Existing building versus new-build assessment

    A useful way of understanding the difference is to think about the source of the assessment data.
    The Government guidance confirms that where plans are available for an existing building, an assessor must still validate that information through a site inspection.

    That requirement is specifically concerned with existing-building assessments.


    The approach to genuine new-build assessments is different because the assessor is certifying the completed building using the documentation supplied for the construction.

    When may a site visit not be required?

    For a genuine new-build EPC, the assessment can be based on appropriate documentary evidence supplied by the developer, designer or other responsible project party.

    Examples include a building that:

    Has been constructed completely from new

    For example:

    A new office is constructed from foundations upwards on a previously vacant site.
    The assessor can work from the completed design and as-built documentation.

    Is undergoing its first shell-and-core fit-out

    A shell-and-core building may be completed before the final occupier's services and internal fit-out are installed.


    The Government guidance recognises shell-and-core buildings and explains that where the building is expected to be conditioned but services have not yet been installed, an EPC must still account for the expected fixed services.


    The important concept is first fit-out.

    A shell-and-core condition does not continue indefinitely.

    Once a unit has been fully fitted out and occupied, it cannot later be stripped back and treated as a brand-new shell-and-core building simply because the services have been removed.


    Has undergone a change of energy status

    The Building Regulations define a change to a building's energy status as a change that causes the building to become subject to the energy-efficiency requirements where it was not previously subject to them.


    For example:

    An unheated agricultural or storage building is converted into a heated office complex.
    The previously unconditioned building has now become a conditioned building.

    Regulation 22 requires work to be carried out where necessary so that the building complies with the applicable requirements of Part L.

    Care is required here.

    A change of energy status is not the same thing as simply adding heating to one room within an otherwise conditioned building.

     

    Extensions and the 100 m² / 25% rule

    Large extensions to non-domestic buildings require particular attention.

    A commonly encountered rule is:

    The extension must be greater than 100 m² AND greater than 25% of the total useful floor area of the existing building.
    Both conditions must be satisfied.
    This threshold is used within Building Regulations guidance to determine when a large extension should follow the new-building approach to Part L.

    When would a site visit normally be required?

    Not every project that looks new is actually a new-build assessment.
    A site visit would normally be expected where the assessor is assessing an existing conditioned building.


    Examples include the following:
    Existing building stripped out and refurbished
    • Consider an office that has existed for many years.
    • The occupier moves out and the building is stripped back internally. New lighting, HVAC and finishes are installed.
    • The building has not suddenly become a new building.
    • It remains an existing building that has undergone refurbishment.
    • A survey is therefore required to establish what actually exists.
    • The Government guidance gives a similar example of a building undergoing a complete internal refit. A refit alone does not necessarily trigger the requirement for a new EPC.

    Part of an existing building becomes conditioned
    • Suppose a warehouse already contains heated offices.
    • The warehouse storage area has previously been unheated but heating is now installed.
    • This is not the same as constructing an entirely new building.
    • The assessor must establish the existing building and the altered section correctly.

    Smaller extension
    • Where an extension does not meet both of the large-extension thresholds discussed earlier, it does not automatically follow the new-building approach applicable to large extensions.
    • If an EPC is required for the whole existing building, the assessor must appropriately assess the existing building as well as the extension.

    Do not confuse an EPC trigger with Building Regulations work

    This distinction is extremely important.


    The fact that Building Regulations apply to work does not automatically mean that a new EPC is legally required.


    For example, an existing commercial building may undergo:
    • replacement heating;
    • new lighting;
    • air-conditioning replacement;
    • an internal refurbishment;
    • or insulation upgrades.

    The work may need to comply with Building Regulations.


    However, that does not necessarily create an EPC trigger.


    The Government guidance gives the example of a complete internal refit where no new separately occupied parts have been created. It states that a new EPC is not automatically required solely because of the refit.


    This gives us an important rule:
    Building Regulations compliance and the requirement to produce an EPC are related, but they are not the same question.
    An assessor should establish why the EPC is being produced before deciding how to approach the assessment.

    The assessor's role on a new-build EPC

     
    On a genuine new-build assessment, the assessor is acting as an energy assessor and certifier, not as the project's Building Control Officer.


    The assessor needs sufficient evidence to correctly model the building that has been constructed.


    However, the assessor is not responsible for independently approving whether the building satisfies every aspect of Building Regulations.


    For example, the assessor may receive:
    • construction specifications;
    • U-value calculations;
    • glazing specifications;
    • HVAC schedules;
    • lighting schedules;
    • air-pressure test certificates;
    • commissioning information;
    • BRUKL documents;
    • drawings;
    • and Building Control documentation.

    The assessor uses these documents to build and support the EPC model. The assessor should not redesign the building or substitute their judgement for Building Control.


    However, this does not mean evidence should simply be accepted without question.


    If documents conflict, appear incomplete or clearly do not relate to the building being assessed, the assessor must resolve that discrepancy before lodging the EPC.

    Proposed drawings are not automatically as-built evidence

    This is one of the most important principles when completing a new-build EPC.


    A drawing marked:
    Proposed
    or
    Construction Issue
    does not automatically prove that the building was actually constructed exactly that way.


    Buildings change during construction.


    For example:
    • insulation products may change;
    • boilers may be substituted;
    • lighting layouts may be altered;
    • window specifications may change;
    • HVAC equipment may be replaced with an equivalent model;
    • room layouts may move;
    • or control systems may change.

    The assessor therefore needs confirmation of the as-built condition.


    Where drawings and specifications were originally produced for design purposes, obtain written confirmation that the completed building was constructed in accordance with those documents, together with details of any changes.


    The new NDEA Minimum Evidence Requirements specifically require as-built confirmation identifying differences from the design where applicable. Convention 2.06 states the type of acceptable documentary evidence.
     

    Evidence requirements changed on 1 October 2026

    From 1 October 2026, EASOB introduced standardised Minimum Evidence Requirements across accreditation schemes in England and Wales.


    For NDEAs, these requirements establish the minimum evidence that must be retained to support the assessment.
    The requirements apply to both existing and newly constructed non-domestic buildings, although the evidence expected is not identical in each case.


    For new buildings, evidence may include:
    • the assessment data file;
    • floor plans;
    • elevations and sections;
    • zone drawings and schedules;
    • construction specifications;
    • building-services information;
    • product literature;
    • calculations;
    • airtightness information;
    • as-built confirmation;
    • and evidence supporting recommendations.

    The underlying principle is simple:

    An auditor should be able to understand and reproduce the assessment from the evidence retained.
    The new requirements do not change the calculation methodology themselves. They formalise the baseline level of evidence that assessors must retain.

    References and further reading

    GOV.UK - A Guide to Energy Performance Certificates for the Construction, Sale and Let of Non-Dwellings
    Covers EPC triggers, new construction, modifications, shell-and-core buildings and the responsibilities of the assessor and building owner.

    https://www.gov.uk/government/publications/energy-performance-certificates-for-the-construction-sale-and-let-of-non-dwellings--2


    The Building Regulations 2010
    Refer particularly to Regulation 22 regarding a change to a building's energy status.

    https://assets.publishing.service.gov.uk/media/63d8edbde90e0773d8af2c98/Approved_Document_L__Conservation_of_fuel_and_power__Volume_2_Buildings_other_than_dwellings__2021_edition_incorporating_2023_amendments.pdf


    EASOB - NDEA Minimum Evidence Requirements v1.1
    Effective from 1 October 2026 for England and Wales.

    https://easob.co.uk/NDEA_Minimum_Evidence_Requirements.pdf


    Non-Domestic EPC Conventions for England and Wales
    The conventions should be used alongside the applicable NCM methodology and accreditation-scheme guidance when determining assessment inputs and handling missing services.
    https://www.uk-ncm.org.uk/filelibrary/Commercial-EPC-EW-Conventions-Issue_9_v0.1.pdf

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