The EPC is a compulsory document included in a Home Information Pack which a seller must, by law, provide when putting their property on the market. The EPC will show an energy efficiency rating for the energy performance of a home from A to G; where A is very efficient and G is very inefficient. This is similar to the ratings now displayed on sale for domestic appliances such as refrigerators and washing machines.

The rating is based on factors such as age, property layout, construction, heating, lighting, and insulation. The ratings are standard so the energy efficiency of one home can easily be compared with another. The average rating for a home is a D/E. Accompanying the energy efficiency rating is an environmental impact rating of the CO2 emissions relating to the property. A recommendation report forms part of the certificate and provides a range of improvement measures which could improve a home's energy performance.