A SAP calculation works out the rating that is required in order to produce a Predicted Energy Assessment and an On-Construction Energy Performance Certificate for a new domestic building.
A SAP calculation indicates a score for the predicted annual energy cost for the new building based on:
- The elements of structure;
- The internal lighting;
- The heating;
- The hot water system;
- Any renewable technologies installed in the home.
The higher the score the lower the running costs, with 100 representing zero energy cost. Dwellings with a rating in excess of 100 are net exporters of energy.
The model used to produce a SAP calculation is largely location independent. It is also based on a notional occupancy to overcome the different ways in which people use their homes. As a result, SAP calculations allow the energy running costs of dwellings anywhere in the UK to be compared.