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Heat pumps for renovations

01 Nov 2021


There’s been a lot of debate in the news recently about how the UK is soon to turn its back on gas boilers in favour of heat pumps.

We have known about this for a couple of years in the new build sector, and it’s expected that heat pumps will be installed in the majority of new homes within the next five years.

But this push into the existing housing stock may come as a surprise to builders who deal with the conversion of old office and farm buildings and are used to dealing with a simpler set of energy targets.

Here’s a quick look at what’s expected to change in the coming years:


When converting an old building into a dwelling, you don’t currently have to meet a Target Emission Rate as you do for a new build. This isn’t expected to change in 2022, so the use of heat pumps won’t be as essential as on a new build… But there are two other rules to keep in mind instead:

Firstly, the Minimum Energy Efficiency Standard (MEES). Under current rules, private homes must achieve an E rated EPC before they are rented out. The landlord needs to invest to improve F and G rated buildings. The Government intends to scale up the MEES rules over the next decade, with the current proposals suggesting that by 2028, private rentals must achieve a C rating or higher.

As the targets for MEES are tightened, more uninsulated rentals with expensive, inefficient heating systems will need to be improved. Replacing old systems with heat pumps will be one of the options suggested to landlords, along with better insulation, replacement glazing and solar panels.

But that’s not all – there’s a separate law in development which is currently sitting on a Westminster drawing board; it’s suggesting that from 2026, the installation of oil and LPG boilers will be banned, with mains gas boilers to follow in the mid 2030s. This will apply to replacement installs as well as new builds and conversion projects.

Such a law would force the renovation market towards heat pumps, biomass or maybe a hydrogen based alternative (once this technology becomes mainstream).


If you’re changing the heating system in a house, Building Regulations say the new system shouldn’t generate higher levels of CO2 than the system being replaced.

In real-life words, that means your new boiler must be more efficient than the old one. It also means that you shouldn’t replace a heat pump with a gas boiler or panel heaters, because both aren’t as efficient as a heat pump. Effectively, once you switch to a heat pump, the current regulations don’t let you switch back.

There’s no obligation in Building Regulations to replace an existing heating system, providing it works and is safe. The switch to low energy heating isn’t coming at the cost of ripping out perfectly usable systems.


Looking at the bigger picture, we have the Future Homes Standard, Approved Document L 2021, upgrades to MEES and a potential new law banning the install of fossil fuel boilers. All of these policies are steering the construction industry – both new build and existing – on a road towards low energy heating systems using zero carbon fuel.

Just as we’re seeing with the electric car switchover and phase out of petrol and diesel models, our buildings are starting on a similar journey of changing from the combustion engine that is our gas boilers, in favour of a sustainable energy supply.

For more information on regulation changes and how these may impact your future developments, speak to the Energist Technical team.


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Jon Ponting

Energy & Sustainability Specialist


Jon Ponting

Energy & Sustainability Specialist