If you are building a new home in the UK, Building Control will need a set of SAP Calculations prior to any building work.

Part L1A of the building regulations sets stringent targets in England and Wales for carbon emissions and the thermal performance of the building fabric in new build schemes.

What are SAP calculations?

The Standard Assessment Procedure (SAP) is the methodology used by the Government to assess and compare the energy and environmental performance of dwellings. Its purpose is to provide accurate and reliable assessments of dwelling energy performances that are needed to underpin energy and environmental policy initiatives.

SAP works by assessing how much energy a dwelling will consume, when delivering a defined level of comfort and service provision. The assessment is based on standardised assumptions for occupancy and behaviour. This enables a like-for-like comparison of dwelling performance. Related factors, such as fuel costs and emissions of carbon dioxide (CO2), can be determined from the assessment.

SAP quantifies a dwelling’s performance in terms of: energy use per unit floor area, a fuel-cost-based energy efficiency rating (the SAP Rating) and emissions of CO2 (the Environmental Impact Rating). These indicators of performance are based on estimates of annual energy consumption for the provision of space heating, domestic hot water, lighting and ventilation. Other SAP outputs include estimate of appliance energy use, the potential for overheating in summer and the resultant cooling load.

Fabric Energy Efficiency

Homes built after April 2014 in England are also assessed on Fabric Energy Efficiency. This is not a measure of carbon, but energy demand in units of kilowatt-hours per m² per year. How well a home retains the heat it produces will have an impact on its CO2 emissions as well as being assessed separately to gauge compliance.

Fabric Energy Efficiency is assessed using DFEE/TFEE figures. As with emissions the target is set within SAP using a set of baseline values depending on the size of the property.

Do you need help with your new project?

We can undertake Part L Building Regulations compliance assessments for domestic and non-domestic properties, and new or refurbished buildings.

Whether you are an architect, developer, consultant or contractor, our fully qualified energy assessors can provide expertise to demonstrate compliance with building regulations and assist in optimising your project from concept stage to as-built.