An Energy Performance Certificate or “EPC” is created from a home's SAP data. It provides a home with a rating between 1-100 based on the estimated energy costs of the home - the higher the rating the lower the estimated energy costs. This number is then graded in bandings between A and G (which is what you will see), with national targets for every UK home to be at least meet the EPC C standard by 2030.
Every home is legally required to have an EPC rating whenever it is sold, rented or built and gives the resident clear information about the homes energy efficiency and what it may cost to run.