Part L - Conservation of Energy

Building Regulations Part L - Conservation of Energy

What is building regulations part L?

This section of the building regulations sets out the standards for energy performance and carbon emissions of a new or existing dwelling.

Part L is split into four sections:

L1A - New Dwellings

L1B - Existing Buildings

L2A - New Buildings other than Dwellings

L2B - Existing Buildings other than Dwellings

How often are building regulations reviews and updated?

These standards to reviewed and updated every four years and are applied to the SAP (Standard Assessment Procedure) calculation and Carbon Emissions targets for dwellings.

Compliance is gained by going through software using the National Calculation Methodology, which determines the buildings Dwelling Emission Rate or (DER), ensuring that this is in line with Part L.

• SAP (Standard Assessment Procedure) is used for dwellings as new build, change of use or to assess the energy status of a dwelling.

• SBEM (Simplified Building Energy Model) is used for non-dwellings as new building, change of use or to assess the energy status of a non-dwelling.

What is SAP?

SAP is a simplified method to measure and calculate the amount of energy used by a dwelling and convert that into a tonnes of carbon figure. The data for any given dwelling is input and a notional replica of the dwelling is also calculated using default values which produces a Target Emission Rate (TER) which is the minimum allowable standard for the energy performance defined by annual CO2 emissions.

Within Part L, the targets are set for comparison of the DER and TER, and providing the DER is below the TER, compliance has been achieved.

Detailed within is the calculation and compliance targets for the Fabric Energy Efficiency, or (FEE).