SAP calculations (Standard Assessment Procedure) are the UK government’s methodology for measuring energy efficiency & CO2 emission rates for new builds, extended, or converted residential dwellings. They should be submitted to Building Control to ensure compliance with Building Regulations Part L.
Part L1a – SAP assessment is carried out before the start of site works for submission to Building Control. Upon completion, an ‘As Built’ SAP calculation is completed.
Part L1b – For converted buildings, SAP calculations are required to assess the thermal performance of the building fabric, along with the energy requirements of the heating, lighting, and hot water systems.