The Standard Assessment Procedure (SAP) for energy rating of dwellings is a calculation of a building’s energy efficiency. SAP ratings are scored on a scale from 1 to 100 where 1 is the worst and 100 will indicate no heating/hot water cost. It is possible to achieve a higher score than 100 with the use of micro generation exported to the national grid.

A Target Carbon Dioxide Emission Rate (TER) has to be calculated within the Standard Assessment Procedure (SAP).

This will be based on a notional dwelling built to the 2002 standards with a target reduction of 20%. The actual Dwelling Carbon Dioxide Emission Rate (DER) must then be no worse than the TER. The new SAP 2005 incorporates all these calculations.