Isambard Environmental

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Part L1A SAP Calculations

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The Standard Assessment Procedure (SAP) is the government’s methodology to assess and compare the energy performance of dwellings against Part L1A of the Building Regulations 2013 for new residential dwellings.  Energy use and CO2 emissions of the proposed dwelling are compared against those of a notional dwelling of the same size, shape and orientation.

The Dwelling Emission Rate (DER) measures the CO2 emissions and the Dwelling Fabric Energy Efficiency (DFEE) how much heat is lost through the fabric of the dwelling.  Compliance with Part L1A is achieved when the DER and DFEE of the proposed dwelling are lower than the Target Emission Rate (TER) and Target Fabric Efficiency Rate (TFEE) of the notional dwelling.

Factors which influence the DER and DFEE include: the amount of insulation and glazing; type of space and water heating and heat emitters and controls; and air tightness.

Using our experience and detailed technical knowledge we can identify the most suitable and cost-effective strategies in order to achieve increasingly challenging energy and CO2 targets and prepare the SAP calculations and Energy Performance Certificate (EPC) as required by Part L1A.  

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