Building Regulations Approved Document L is a key component of the UK Building Regulations framework. It provides statutory guidance on the conservation of fuel and power in buildings, ensuring that new builds, renovations, and retrofits meet specific energy efficiency standards.
It is divided into two volumes:
- Volume 1: Dwellings – Focused on energy efficiency requirements for new and existing residential properties.
- Volume 2: Buildings other than dwellings – Addresses energy efficiency in non-residential buildings.
Approved Document L ensures compliance with Part L of Schedule 1 to the Building Regulations 2010, which mandates that construction work must incorporate measures to conserve energy and reduce carbon emissions.
Key Provisions
- Thermal Performance Standards
- Sets the minimum U-values (thermal transmittance) for walls, roofs, floors, windows, and doors.
- Requires the use of high-performance insulation and glazing to reduce heat loss.
- Air Tightness and Infiltration
- Buildings must be designed and constructed to minimise air leakage.
- Air permeability testing (commonly known as a blower door test) is required for new builds to demonstrate compliance.
- Heating and Hot Water Systems
- Specifies efficiency standards for boilers, heat pumps, and other heating systems.
- Encourages the use of low-carbon technologies, including solar panels and heat recovery systems.
- Renewable Energy Integration
- Promotes the incorporation of renewable energy sources such as photovoltaic (PV) panels and solar thermal systems to reduce reliance on non-renewable fuels.
- Lighting Efficiency
- Sets standards for the use of energy-efficient lighting, such as LED systems, to reduce electricity consumption.
- Retrofit Standards
- Provides guidance for improving the energy efficiency of existing dwellings, including loft and cavity wall insulation, draught-proofing, and replacement of inefficient windows.
Approved Document L plays a vital role in helping the UK meet its net-zero carbon emissions targets by 2050. It aligns with broader government initiatives, such as the Future Homes Standard, which aims to ensure all new homes are zero-carbon ready by 2025. For retrofits, it complements PAS 2035, a framework for managing energy efficiency improvements in existing buildings.