SAP Calculations (OCEPC)

A SAP rating is the technical calculation that is required in order to produce a Predicted Energy Assessment (PEA) and an On Construction Energy Performance Certificate (OCEPC) both of which are reports that extract information from the supporting SAP calculation.

A SAP calculation is simply a home energy rating that seeks to calculate a score between 1 and 100 for the property derived from:

  • The built structure of the home
  • Its heating and hot water system
  • Internal lighting
  • Any renewable technologies used in the home.

The higher the number the lower the fuel running costs with 100 representing zero energy cost. Dwellings with a rating in excess of 100 are net exporters of energy.

In simple terms SAP calculations allow comparison of the energy running costs of dwellings anywhere in the United Kingdom in a similar manner to the well-known comparison of fuel economy in cars expressed in miles per gallon. This is achieved because the calculations are predominantly location independent and are based upon a notional standard occupancy that overcomes variations associated with physical location and the differing ways in which people utilise their homes.

A SAP calculation is normally a desk exercise. The assessor does not usually visit the dwelling being assessed. The client submits drawings, plans and specifications of the development to the assessor.