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Home/Glossary/Energy Performance Requirement (Part L)
Energy & Insulation

Energy Performance Requirement (Part L)

Building regulations Part L (Conservation of Fuel and Power) sets the energy performance requirements for new extensions and modifications to existing dwellings. For extensions, Part L requires new elements to meet individual maximum U-values and overall building fabric energy efficiency to not be worse than before. A notional building assessment or SAP calculation may be required for large extensions.

Related terms

U-ValueSAP RatingEPC (Energy Performance Certificate)
Electrical Installation CertificateEnforcement Notice

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