Part L Building Regulations change - what to expect?

17 March 2021 Kingspan Water & Energy

What do the 2021 Part L Building Regulation changes mean for specifiers, developers and installers?

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With Building Regulations Part L changes due to come in thick and fast over the coming four years, Andrew Ogden, Technical Director ‑ Hot Water Storage at Kingspan Water & Energy, shares his views on how specifiers, developers and installers can be prepared.

It’s long been old news that new homes won’t be connected to the gas grid from 2025; what’s been less clear is how the move away from fossil fuels to low carbon heating would happen. With the results of The Future Homes Standard 2019 Consultation on changes to Part L and Part F finally published, there’s now a clearer – and quicker – roadmap to a lower-carbon future for new homes.
In our view, this brings opportunities for developers and specifiers to take a fresh look at fossil-fuel-free heating technologies and new opportunities for plumbing and heating installers to be ahead of the game.
What are the 2021 changes to Part L of the Building Regulations?
Part L is all about the conservation of fuel and power in new dwellings. The Future Homes Standard 2019 Consultation1, due for full implementation in 2025, was all about if and how that plan could be accelerated. The overwhelming response was “yes, it should be”; the result being that from mid-2022, new homes will have a 31% reduction in CO2 when compared to current standards. You may sometimes see this called “Option 2”, as that’s how it was referred to in the Consultation.
Making this CO2 reduction a reality will be new interim Part L and Part F legislation from December 2021 that will be enacted from June 2022; before bigger changes in 2025 that will mean a 75% reduction in CO2 in new dwellings when compared to today, along with a new focus on rating primary energy efficiency as well as CO2.
Which begs the question, what will the interim December 2021 uplift to Part L legislation likely mean in practice?
Expect to see more heat pump and solar photovoltaic (PV) systems
We do know that homes will have to have top-notch fabric standards, be future-proofed to be able to achieve zero carbon, and have low carbon heating. The Government’s own response to Future Homes Standard Consultation admits that the interim December 2021 uplift to Part L won’t see an immediate rush to install heat pumps, simply because the skills and supply aren’t yet set up at this scale.2
Nonetheless, heat pumps are clearly a key part of the Government bid to convince developers to favour them over other heat sources, as the Consultation reports states, “a home built … with a heat pump will still have a lower capital cost than one built with a gas boiler.”2
Builders, developers and local authorities are supportive of this stance too: when asked about heat pumps and heat networks in the Consultation, 70% of respondents agreed heat pumps should play a role.3
Industry and Government are clearly lined up here; and we have a collective responsibility to make lower carbon heating happen. As the Government said, it is “important to build the market for them [heat pumps] now. Heat pumps are highly efficient, providing around three times the amount of heat compared to the electricity used.”4
The exact detail of the December 2021 uplift in standards will come out of the Government’s follow-up consultation, The Future Buildings Standard5, which is open until 13th April 2021. As well as heat pumps, we can also expect to see an increase in the use of solar photovoltaic (PV) panels; along with a further update to SAP6 to SAP 10.2, which we envisage will launch to coincide with the above timetable.
Notices or plans submitted by developers after June 2022 must then be built in line with the new Part L interim standards. Those submitted before June 2022 need to start work on individual buildings by June 2023 for older Part L standards to apply. Developers can see more details on transitional arrangements in the Consultation response document.7
What will happen between 2021 and 2025 to Part L standards?
As already mentioned, there’ll be interim legislation for Part L, as well as Part F and Overheating Regulations made by December 2021; with these coming into effect from June 2022.
Following plenty of behind-the-scenes work, Spring 2023 will then see the launch of a Technical consultation on the proposed specification for the Future Homes Standard, with regulations being made in 2024 for implementation in 2025.8

We can expect that under the 2025 Future Home Standard, CO2 emissions will be at least 75% lower than homes built today; and that “heat pumps will become the primary heating technology for new homes under the Future Homes Standard.”4

How should specifiers, developers and plumbing and heating installers prepare for the Part L changes?
We’d urge specifiers, developers and plumbing and heating installers to start to prepare now. June 2022 will be with us before we know it.
We’d recommend specifiers and developers familiarise themselves with the Future Building Standards Consultation which closes on 13th April; and consider responding to it. The results of this consultation will feed into the exact legislation changes you can expect to see from June 2022, including the iterative development and launch of SAP 10.2.
We’d also advise understanding SAP implications when specifying hot water and heating systems in new homes, when taken alongside homeowner expectations, costs and performance trade-offs. For example:

  • The time taken to heat water vs time taken to use water
  • The availability of the heat source and the time the hot water is needed
  • The energy used vs the time taken to heat the water

For plumbing and heating installers, we would recommend upskilling in low carbon heating systems, so you and your business are ready to be able to advise on and install heat pump and/or solar photovoltaic systems. There are accredited courses throughout the country and face-to-face training is likely to see an uplift after future easing of coronavirus restrictions. The January 2021 blog on the Kingspan Cylinders website has details of some available course options.
You may also wish to consider if there is an opportunity for your business to install low carbon heating-compatible hot water cylinders; for example in nearly new homes where a cylinder wasn’t installed or properties wanting to upgrade their hot water system to run of solar or a heat pump.
Lower and zero carbon is future for all UK housing stock
Longer-term, we can expect to see the drive for lower-carbon energy in homes be rolled out more extensively to the UK’s current housing stock. The Green Homes Grant may not have had the best publicity recently but we can safely assume that other incentive programmes will follow to encourage the investment required to collectively get the UK to a zero-carbon future.
For manufacturers such as Kingspan, we know we need to be on the front foot to keep up with demand for low carbon heating in the homes of tomorrow.

  1. Future Homes Standard Consultation:
  2. Future Homes Standard Consultation Response: page 29, sections 3.12-3.15.
  3. Future Homes Standard Consultation Response: page 14, section 2.12.
  4. Future Homes Standard Consultation Response: page 16, section 2.21.
  5. The Future Buildings Standard: Consultation document:
  6. SAP:
  7. Future Homes Standard Consultation Response: pages 102-3.
  8. Future Homes Standard Consultation Response: pages 23-4, Table 4.
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