What is a SAP?

Updated: 19 Jan 2019
Good insulation will improve your home's SAP rating
Roof space insulation
SAP has been adopted by government as part of the UK national standard for calculating the energy performance of buildings.
Every new house has to have a SAP rating.  It provides a simple means of reliably estimating the energy efficiency performance of your home.
SAP ratings are expressed on a scale of 1 to 100 - the higher the number, the better the rating. Thus it is similar to the fuel consumption of a car under standard driving conditions. SAP is calculated by a procedure which is specified in Building Regulations, and which predicts heating and hot water costs.

These costs depend on the insulation and air tightness of the house, and on the efficiency and control of the heating system. The calculation uses the Building Research Establishment's Domestic Energy Model (BREDEM).