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Preparing for the transition to the new Future Homes Standard

Preparing for the transition to the new Future Homes Standard: here’s what you need to know about the Part L 2021 uplift

In June 2022, Part L 2021 (conservation of fuel and power) of the Building Regulations is due to come into force. Its purpose is to pave the way for the Future Homes Standard (FHS) – scheduled to be introduced in 2025 – which the government anticipates will ensure new houses are built with ‘world-leading levels of energy and efficiency’.

Here, our Head of Design and Technical Services, Gareth Rouse, explores what the Part L uplift means in practice and what you can do to ensure your business is ready.

“The Part L 2021 uplift brings with it more demanding U-value targets for all building types in a bid to deliver a meaningful reduction in carbon emissions. Under the FHS, the building fabric standards will be pushed even further. The key changes to be aware of are the revised package of performance metrics, tighter compliance and new transitional arrangements that will now be applied to individual homes rather than whole developments.


Current Part L 2013 metrics Proposed Part L 2021 metrics
I.            CO2 emission target

II.          Fabric energy efficiency target

III.         Minimum standards for fabric and fixed building services


I.            Primary energy target

II.           CO2 emission target

III.          Fabric energy efficiency target

IV.          Minimum standards for fabric and fixed building services


The CO2 emission target and fabric energy efficiency target metrics remain in the new standard, but they are joined by the new primary energy target metric. This is a measure of the energy used in dwellings, but it also takes account of upstream energy uses. Its purpose is to make sure that new homes are energy efficient and make good use of national energy resources.

The minimum performance criteria for building fabric elements (U-values) are being reduced under the new standard. Here at Forterra, our technical team can offer guidance and support in choosing flooring and wall products, and they can arrange official U-value assessments. The key to getting the best and most efficient result is to speak to your suppliers as early as possible in the specification stage.

An important issue the government is keen to address is the performance gap between design intent and actual built performance. To support this, a number of new measures are being introduced, including a new compliance report called the Building Regulations England Part L, or BREL as it will be better known, which will be incorporated into an updated version of SAP. In introducing it, the government is seeking to ensure that building control bodies will be provided with the same clear information for every home built, creating a more unified approach than at present.

The uplift to Part L will be quite a shake-up, and it’s worth noting that the standard is even more stringent for work to existing homes. At Forterra, we’ve been working on new U-values for wall and floor constructions, as well as working on a number of new product developments.

The next three years or so should prove to be an interesting time for both building products manufacturers and the construction industry and I’m excited to see what progress will be made – I think we should start to see some fascinating innovations.”

For more information, including key dates to be aware of, download our briefing paper, In brief: The Future Homes Standard 2025 and Part L 2021.  

About Gareth Rouse