The Standard Assessment Procedure (SAP) for the energy rating of dwellings is the methodology currently used by the government to estimate the energy performance of homes. The methodology has 2 main uses:

• to demonstrate compliance of new homes with Part L of the Building Regulations

• to generate Energy Performance Certificates (EPCs) for all homes, which advise occupants, prospective buyers, landlords, and renters of the energy performance of a property

Non-domestic buildings use a different methodology, called the Simplified Building Energy Model (SBEM).