How to Read an EPC Certificate, A Complete Guide to Energy Performance Ratings

What is an EPC Certificate?

An Energy Performance Certificate (EPC) is a document that rates the energy efficiency of a property on a scale from A (most efficient) to G (least efficient). EPCs are produced by accredited domestic energy assessors and are required whenever a property is built, sold, or let in England, Wales, and Scotland.

The A–G Rating Scale

The rating is calculated using the Standard Assessment Procedure (SAP), a methodology developed by the Department of Energy Security and Net Zero. The SAP score translates to a letter band:

The average property in England and Wales has an EPC rating of D.

The Two Ratings: Current vs Potential

Every EPC shows two ratings side by side: the current energy efficiency rating and the potential rating. The potential rating shows what the property could achieve if all the recommended improvements were implemented.

CO2 Emissions and Running Costs

Below the rating bands, the EPC shows the property's estimated CO2 emissions (in tonnes per year) and estimated energy costs. These are based on standardised assumptions about occupancy and behaviour, so actual bills will vary.

The Recommendations Section

The most valuable part of an EPC for homeowners is the recommendations section. This lists specific improvements, such as loft insulation, cavity wall insulation, solar panels, or a heat pump, ranked by cost-effectiveness. Each recommendation shows:

• The estimated cost of installation
• The estimated annual saving on energy bills
• The improvement it would make to the EPC rating

Who Produces EPCs?

EPCs can only be produced by a Domestic Energy Assessor (DEA) registered with an accredited scheme. In England and Wales, assessors are accredited by bodies such as Elmhurst Energy, Stroma Certification, and ECMK. The completed certificate is lodged with the national EPC register maintained by the Ministry of Housing, Communities & Local Government.

How to Find an EPC on Property Passport UK

You can view the EPC for any property in England and Wales free on Property Passport UK. Search by postcode or address, each property page shows the current EPC band, SAP score, certificate date, and improvement recommendations sourced directly from the official EPC Register.