SAPS EXPLAINED

The Standard Assessment Procedure (SAP) is adopted by Government as the UK methodology for calculating the energy performance of dwellings. The calculation is based on the energy balance taking into account a range of factors that contribute to energy efficiency:

• materials used for construction of the dwelling
• thermal insulation of the building fabric
• ventilation characteristics of the dwelling and ventilation equipment
• efficiency and control of the heating system(s)
• solar gains through openings of the dwelling
• the fuel used to provide space and water heating, ventilation and lighting
• renewable energy technologies.

The calculation is independent of factors related to the individual characteristics of the household occupying the dwelling when the rating is calculated, for example:
household size and composition ownership and efficiency of particular domestic electrical appliances individual heating patterns and temperatures.
Ratings are not affected by the geographical location, so that a given dwelling has the same rating in all parts of the UK.

SUMMARY
The Government’s Standard Assessment Procedure (SAP) for assessing the energy performance of dwellings. The indicators of the energy performance are energy consumption per unit floor area, an energy cost rating (the SAP rating), an Environmental Impact rating (based on CO2 emissions) and a Dwelling CO2 Emission Rate (DER). The SAP rating is based on the energy costs associated with space heating, water heating, ventilation and lighting, less cost savings from energy generation technologies. It is adjusted for floor area so that it is essentially independent of dwelling size for a given built form. The SAP rating is expressed on a scale of 1 to 100, the higher the number the lower the running costs. The Environmental Impact rating is based on the annual CO2 emissions associated with space heating, water heating, ventilation and lighting, less the emissions saved by energy generation technologies. It is adjusted for floor area so that it is essentially independent of dwelling size for a given built form. The Environmental Impact rating is expressed on a scale of 1 to 100, the higher the number the better the standard. The Dwelling CO2 Emission Rate is a similar indicator to the Environmental Impact rating, which is used for the purposes of compliance with building regulations. It is equal to the annual CO2 emissions per unit floor area for space heating, water heating, ventilation and lighting, less the emissions saved by energy generation technologies, expressed in kg/m2/year.