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What Is an EPC? — Energy Performance Certificate
A plain-English guide to Energy Performance Certificates: ratings A-G, when you need one, costs, improvement measures, and the EPC register in England and Wales.
Definition
An EPC (Energy Performance Certificate) is a document that rates the energy efficiency of a building on a scale from A (most efficient) to G (least efficient). It includes the current rating, a potential rating showing what could be achieved with improvements, estimated energy costs, and a list of recommended improvement measures. EPCs have been required for property sales and lettings in England and Wales since 2007 under the Energy Performance of Buildings Regulations.
When Is It Used?
EPCs are required whenever a property is built, sold, or rented. They are also relevant for landlords needing to meet the Minimum Energy Efficiency Standards (MEES), homeowners applying for government grants (such as the Boiler Upgrade Scheme), and for assessing a property's environmental impact. All valid EPCs are published on the EPC Register, which is publicly searchable.
Key Facts
- Ratings: A (92-100), B (81-91), C (69-80), D (55-68), E (39-54), F (21-38), G (1-20)
- Average UK home EPC rating is D (approximately 60-65 points)
- Valid for 10 years from date of issue
- Must be produced by an accredited Domestic Energy Assessor (DEA)
- Minimum rating of E required for rental properties (MEES regulations)
- Penalty for failing to have an EPC when required: up to £5,000 for commercial properties
- New-build EPCs are generated from the SAP calculation and are typically rated B or above
- The EPC Register is publicly searchable at gov.uk
Related Calculators
Use the EPC Rating Estimator to get an approximate rating, or the U-Value Calculator to check wall and roof performance. The Heat Loss Calculator shows the effect of insulation improvements on energy use. See also the SAP glossary entry.
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How We Calculate This
Frequently Asked Questions
You need an EPC when selling a property, renting out a property (new tenancy or renewal), or when a building is newly constructed. The EPC must be available to prospective buyers or tenants at the earliest opportunity and must be included in any property listing. An EPC is valid for 10 years. You do NOT need an EPC for listed buildings (in some circumstances), places of worship, temporary buildings used for less than 2 years, or industrial sites with low energy demand.
Since April 2020, all rental properties in England and Wales must have a minimum EPC rating of E (the Minimum Energy Efficiency Standards - MEES). Landlords cannot grant a new tenancy for properties rated F or G unless they have registered a valid exemption. The government consultation (December 2024) proposes raising the minimum to C for all private rental tenancies by 2030.
An EPC for a typical 3-bedroom house costs between £60 and £120. The assessment takes about 45-60 minutes and must be carried out by an accredited Domestic Energy Assessor (DEA). The assessor will inspect the property, measure rooms, check insulation, heating systems, windows, and lighting, then produce the certificate using approved software (RdSAP for existing dwellings).
The most effective improvements typically include: loft insulation (topping up to 300 mm per current AD L 2021 best practice), cavity wall insulation, upgrading to a condensing boiler or heat pump, double or triple glazing, LED lighting throughout, hot water cylinder insulation jacket (80 mm), draught-proofing, and smart heating controls. The EPC report includes specific recommendations ranked by cost-effectiveness for your property.
An EPC for an existing dwelling uses Reduced Data SAP (RdSAP), which is a simplified version based on a site survey and assumptions. A full SAP calculation is required for new-build dwellings to demonstrate Part L compliance and uses detailed design data including exact insulation thicknesses, boiler efficiencies, and thermal bridging values. New-build EPCs are generated from the as-built SAP calculation.
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Last updated: March 2026
Verified against UK standards · estimates only, confirm with your supplier.