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Non-Domestic Energy Performance Certificates

Non-domestic buildings are all buildings that do not fall into the category of buildings solely for residential use (see Domestic EPCs).

There is a legal requirement for EPCs to be provided on the sale, letting or construction of buildings other than dwellings with a floor area greater than 50m2 that contain fixed services that condition the interior environment. Non-dwellings are responsible for almost 20 per cent of the UK’s energy consumption and carbon emissions.

Non-domestic Energy Performance Certificates (EPCs) are a rating scheme to summarise the energy efficiency of buildings. The building is given a rating between A (Very Efficient) РG (Very inefficient), and will also include tips about the most cost effective ways to improve the property’s energy rating. It should be noted that the numerical scale for non-domestic buildings is the opposite of that for domestic properties. 

Energy Performance Certificates are used in many countries.

For non-domestic (all non-residential) properties this is a carbon based (CO2 emissions) metric, allowing owners, landlords, tenants and purchasers to compare different properties in terms of environmental impact. 

The methodology assesses the actual building against a notional building of the same size and construction as the actual. The notional building is deemed to be energy efficient and the resulting rating compares the performance of the actual building to that. It makes no allowance for the hours of actual use nor the actual energy consumption incurred by the occupier.

There are three levels of building, Level 3, Level 4 and Level 5. The complexity of the property and the services used by that building will determine which level it falls under. The Non-domestic Energy Assessor must be qualified to the level of the building to carry out the inspection.

The comparison between properties of similar size and age however still remains valid. 

The A to G scale for non-domestic EPCs

The A to G scale is a linear scale based on two key points defined as follows:

  • The zero point on the scale is defined as the performance of the building that has zero net annual CO2¬†emissions associated with the use of the fixed building services as defined in the Building Regulations. This is equivalent to a Building Emissions Rate (BER) of zero.
  • The border between grade B and grade C is set at the Standard Emissions rate (SER)‚Ć and given an Asset Rating of 50. Because the scale is linear, the boundary between grades D and grade E corresponds to a rating of 100.

EPC recommendations

The certificate includes recommendations on ways to improve the property to save money energy and carbon.¬† The recommendations may appear general in tone, but they are bespoke to the actual property. EPC recommendations are cost effective in improving the¬†energy efficiency¬†of the property, but also include more expensive options (described as ‘longer term measures’) which are less cost effective in the short term.¬†


The energy assessment needed to produce a non-domestic EPC must be carried out by a qualified non-domestic energy assessor, registered with an approved accreditation body. The UK Government has set up a publicly accessible central register of Assessors.

The calculation of the energy rating on the EPC is based on the Standard Building Energy Model (SBEM) Procedure created for the UK Government by the UK Building Research Establishment.

The Assessor will visit the property, examine key items such as all elements of building fabric (walls, floors, roofs, windows and doors) and all installed building services and controls (heating, cooling, ventilation, air-conditioning, lighting ). The exercise is entirely non-invasive (visual only).

Once back in the office, the Assessor inputs the observations into a software program which performs the calculation of energy efficiency. The energy assessor can either:

  • Assume the pre-set values for energy efficiency of the various elements of construction and building services (‘as built’ to¬†Building Regulations¬†for the dwelling’s age) and the software will make assumptions on the insulation properties of various elements of the property based on age and construction type, or
  • If the building owner can produce documentary evidence on what has been built or installed, Assessor has the ability to over-ride these assumptions if visual or written evidence is provided in support.

The accuracy of the recommendations will depend on the inspection standards applied by the assessor. All registered Ass

essors are audited by their accreditation bodies in order to maintain standards. An MEP Assessor has a high level of skills, maintained by regular CPD training which frequently exceeds the minimum requirement of their accreditation body and usually provides advice and guidance not generally offered by others.  

The program gives a single number for the rating of energy efficiency, and a recommended value of the potential for improvement. 

The landlord or owner will have to pay for the survey. As each non-domestic property is unique in terms of use, complexity, fabric construction and building services, it is not possible to provide guidance on the likely cost. 

See an example.

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