Energy Performance Certificates tell you how energy efficient a home is on a scale of A-G. The most efficient homes - which should have the lowest fuel bills - are in band A. The Certificate also tells you, on a scale of A-G, about the impact the home has on the environment. Better-rated homes should have less impact through carbon dioxide (CO2) emissions. The average property in the UK is in bands D-E for both ratings. The Certificate includes recommendations on ways to improve the home's energy efficiency to save you money and help the environment.