Handover & Completion · Mandatory · Completion

Energy Performance Certificate

An Energy Performance Certificate rating the energy efficiency of a building from A to G.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. Building Regs Part L / EPB Regs remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

Legal basis	Building Regs Part L / Energy Performance of Buildings Regs 2012
Status	Mandatory
Issued by	Accredited Energy Assessor
Rating	A–G
Valid	10 years
Methodology	SAP for dwellings, SBEM for non-domestic

1. The EPC — Statutory Energy Performance Evidence at Completion

The Energy Performance Certificate (EPC) is the statutory evidence of a building's energy performance. It rates the energy efficiency of a building on a scale from A (most efficient) to G (least efficient) and provides an estimate of the annual energy costs. For new buildings, the EPC is produced as part of the building regulations compliance process and must be lodged on the Energy Performance of Buildings (EPB) Register before the building is sold, let, or occupied.

The EPC is based on the as-built energy performance of the property, calculated using the Standard Assessment Procedure (SAP) for dwellings or the Simplified Building Energy Model (SBEM) for non-domestic buildings. The SAP calculation takes into account the construction of the building fabric, the heating and hot water systems, ventilation, lighting, and renewable energy technologies. The air permeability test result is a key input to the SAP calculation and must be incorporated before the EPC is finalised.

The EPC must be produced by an accredited energy assessor who is registered with an approved accreditation scheme. The assessor is responsible for carrying out the assessment, producing the certificate, and lodging it on the EPB Register. The EPC is valid for ten years from the date of issue. It must be provided to the buyer or tenant of the property at the point of sale or letting, and a copy must be displayed in commercial buildings over 500 square metres that are frequently visited by the public.

Sequence matters

The air permeability test result (L12) must feed into the SAP calculation before the EPC is finalised — sequence these correctly. If the EPC is produced before the actual air permeability test result is available, it will be based on an assumed or design value, which may not reflect the actual performance of the building. The final EPC must be based on the actual as-built data, including the measured air permeability.

2. What the Certificate Contains

The EPC provides a standardised summary of the energy performance of the building. Each element of the certificate serves a specific purpose and should be checked to ensure accuracy.

Field	What to check
Property address	The full postal address of the property to which the EPC relates. Confirm that the address is correct and matches the property being completed. Errors in the address on the EPC can cause problems during property transactions.
EPC reference number	The unique reference number assigned to the EPC when it is lodged on the EPB Register. This number can be used to retrieve the certificate from the register and is referenced in property transaction documentation.
Energy efficiency rating	The energy efficiency rating on a scale from A (most efficient) to G (least efficient), expressed as a numerical score. For new dwellings, the minimum rating required under current Building Regulations Part L is typically equivalent to a high B or low A rating, depending on the specification of the building.
Environmental rating	The environmental impact rating on a scale from A to G, based on the estimated CO² emissions of the building. This is a separate rating from the energy efficiency rating and reflects the carbon intensity of the energy used by the building.
Validity	The date of issue and the expiry date of the EPC. An EPC is valid for ten years from the date of issue. A new EPC is required whenever the property is sold or let after the existing EPC has expired, or whenever significant alterations are made to the building that affect its energy performance.
Assessor	The name, accreditation number, and accreditation scheme of the energy assessor who produced the EPC. The assessor must be registered with an approved accreditation scheme. Check that the assessor's accreditation is current and appropriate for the type of property being assessed.
Assessment methodology	The methodology used to produce the EPC. For new dwellings, this is the Standard Assessment Procedure (SAP). For non-domestic buildings, this is the Simplified Building Energy Model (SBEM) or a Dynamic Simulation Model (DSM). The methodology determines how the energy performance is calculated and what inputs are required.
Estimated energy costs	The estimated annual energy costs for the property, broken down by heating, hot water, and lighting. These are based on standardised assumptions about occupancy and usage, not actual energy consumption. They provide a comparative indication of the running costs of the building.
Improvements recommended	A list of recommended improvements that could be made to the building to improve its energy efficiency rating. For new buildings, these recommendations may be limited as the building should already meet current Building Regulations standards. For existing buildings, the recommendations can include insulation upgrades, heating system replacements, and renewable energy installations.
Lodgement	Confirmation that the EPC has been lodged on the EPB Register. Lodgement is a legal requirement — an EPC that has not been lodged is not valid. The lodgement date and the register reference should be confirmed before the EPC is relied upon for completion or property transactions.

3. Common Mistakes

Not commissioning the energy assessor early enough

The energy assessor needs to be engaged early in the project so that the design SAP calculation can be produced alongside the building regulations application. If the assessor is not commissioned until late in the project, there may be insufficient time to produce the SAP calculation, carry out the air permeability test, finalise the EPC, and lodge it on the register before the completion date. Late commissioning is a common cause of completion delays.

Not updating the SAP calculation with the actual air permeability result

The design SAP calculation is based on an assumed air permeability value. The actual air permeability is measured by an air permeability test (pressure test) carried out on the completed building. The actual test result must be entered into the SAP calculation to produce the final as-built SAP, which is then used to generate the EPC. If the SAP is not updated with the actual air permeability result, the EPC will be based on assumed data and will not reflect the true energy performance of the building.

Using an unaccredited assessor

The EPC must be produced by an energy assessor who is registered with an approved accreditation scheme. An EPC produced by an unaccredited assessor is not valid and cannot be lodged on the EPB Register. The accreditation schemes ensure that assessors are trained, competent, and subject to quality assurance checks. Always verify that the assessor is currently accredited before commissioning the EPC.

Not providing the EPC to the buyer or tenant

The Energy Performance of Buildings Regulations 2012 require that the EPC is provided to the buyer or tenant of the property at the point of sale or letting. Failure to provide the EPC is a breach of the regulations and can result in a fixed penalty notice. The EPC should be included in the handover pack for new-build properties and provided to the tenant before they commit to the tenancy for rental properties.

Confusing the EPC with Part L compliance

The EPC and Part L compliance are related but separate. Part L of the Building Regulations sets the minimum energy performance standards that a new building must meet. The SAP calculation is used to demonstrate Part L compliance during the design and construction process. The EPC is the certificate that records the as-built energy performance of the completed building. A building can have a valid EPC without necessarily complying with Part L if the as-built performance differs from the design specification. Both Part L compliance and a valid EPC are required at completion.

4. Frequently Asked Questions

Who is responsible for producing the EPC?▾

The person who is responsible for the building work is responsible for ensuring that an EPC is produced and lodged on the EPB Register. For new buildings, this is typically the developer or builder. For alterations or extensions, this is typically the property owner or the contractor acting on their behalf. The EPC itself must be produced by an accredited energy assessor, but the responsibility for commissioning the assessor and ensuring the EPC is produced rests with the person responsible for the building work.

Can a building be occupied without an EPC?▾

The Energy Performance of Buildings Regulations 2012 require that an EPC is made available to the buyer or tenant before the building is sold or let. For new buildings, the EPC must be produced before the building is occupied. Occupation without a valid EPC is a breach of the regulations and can result in enforcement action by the local weights and measures authority (Trading Standards). In practice, mortgage lenders and conveyancers will require sight of the EPC before completion, so occupation without an EPC is unlikely for properties being purchased with a mortgage.

What is the relationship between the EPC and Part L of the Building Regulations?▾

Part L of the Building Regulations sets the minimum energy performance standards for new and existing buildings. The SAP calculation (for dwellings) or SBEM calculation (for non-domestic buildings) is used to demonstrate compliance with Part L during the design and construction process. The EPC is produced from the final as-built SAP or SBEM calculation and records the energy performance of the completed building. Part L compliance is assessed by the Building Control Body as part of the building regulations process. The EPC is a separate certificate that must be produced by an accredited energy assessor and lodged on the EPB Register. Both are required, but they serve different purposes.

What is the required EPC rating for new homes?▾

The Building Regulations do not specify a minimum EPC rating as such. Instead, Part L sets target values for carbon emissions, fabric performance, and primary energy that a new dwelling must achieve. The SAP calculation determines whether the dwelling meets these targets. In practice, a new dwelling that complies with Part L 2021 (the current edition) will typically achieve an EPC rating of B or above. Some planning conditions and housing standards (such as the Future Homes Standard, expected to take effect from 2025) may require higher performance levels that would result in an A rating.

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