Energy Performance Certificates (EPCs) are now mandatory upon construction, sale or rental of any non-domestic building, whether new or existing. An assessment must be carried out by an accredited assessor and an EPC generated, which gives the building a rating of 'A' to 'G' (where 'A' is the most energy efficient).

The EPC is also accompanied by an Advisory Report (AR) which outlines ways in which energy can be saved and provides recommendations that include the short, medium and long term paybacks of various green technologies. The implementation of these recommendations would reduce the building's CO2 emissions as well as fuel costs.

Approved Document L2A-2006 of the Building Regulations stipulates a full building energy calculation for all newly constructed buildings. The Simplified Building Energy Model (SBEM) software used to produce this documentation is then used to create the EPC which is required prior to the building being occupied.