Building Regulations 2022 – Recent uplift to Part L

What is Part L?

Recently “uplifted” in June 2022 to be more stringent, Part L sets out the requirements of the Building Regulations for the conservation of fuel and power in new and extended buildings, both residential and otherwise. It details the requirements for energy efficiency and low carbon heating within buildings and is being viewed by the government as a preparatory stepping stone towards the implementation of the Future Homes Standard in 2025, helping the UK to move towards net zero. This post will mostly focus on how it relates to new residential works.

What are the changes to Part L?

The headline summation of the Part L uplift is a required reduction of 31% of CO² emissions in new homes over the previous standards. This new standard in energy performance is to be delivered through further improvements to building fabric, modifications to typical dwelling usage, and greater emphasis and inclusion of low carbon technologies and systems.

Some examples of these changes in brief:

• Waste Water Heat Recovery has been included to facilitate the recovery and reuse of heat energy wasted during showers, reducing novel energy demand and thus lowering CO² emissions during everyday use
• Reductions to flow temperature for hot water systems to no more than 55^oC
• Proportional PV installations
• Improvements to maximum permitted U Values for building fabric
• Encourages the use of heat pumps
• Stricter attention to preventing thermal bridging
• New requirements for builders to document and provide photographic information during construction

How can we comply with Part L?

Guidance for Part L can be found in the Approved Document L, and therein can be found the specifications for a “notional dwelling”, which sets out the theoretical specifications for a dwelling that would comply with the uplifted Building Regulations. It defines a set of appropriate values for the building fabric, air tightness, heating and water systems, and others. This can be used as a simplified “cheat sheet” for the design stage, providing a general guiding principle for new dwellings that would comply with the requirements.

Beyond this, the Building Regulation itself requires a number of Rates that assess the energy usage, the energy efficiency and the fabric efficiency of the dwelling. Using SAP 10.2 as an assessment methodology, we are able to determine these rates as targets during the design stage and again as as-built rates after construction, once an air permeability test has been undertaken. Building Control can then be notified with the relevant information.