With heating the UK’s 28 million homes accounting for 13% of all UK greenhouse gas emissions (as of 2023)¹, it goes without saying that decarbonising home heating will be vital to meeting Net Zero by 2050. How we go about this is a separate question, and one where the answer for decision-makers in the sector has increasingly focused primarily on electrification. According to the Climate Change Committee (CCC), for example, nearly all home heating will eventually be electrified, with the majority adopting electric heat pumps².
While electrification will undoubtedly play a very important role in decarbonising home heat, there are a myriad of challenges to making this happen in reality. It will involve significant upfront costs for the consumer, the exchequer or both, remedial work in homes to make them suitable for heat pumps (which will vary from home to home), and a substantial upgrade to our electricity network (both at transmission and distribution level) to manage a winter peak demand it has never had to manage before.
With all these challenges, it seems right to view the challenge of decarbonising heat not just through the narrow lens of electrification. We should be looking at all technological options to consider where these can work alongside electrification to overcome the challenges outlined.
This is where hybrid heating systems come in.
The case for hybrid heating systems
Put simply, hybrid heating systems typically consist of a consumer’s boiler (either existing or replacement) with the addition of a small electric heat pump. The heat pump element provides most of a home’s heating needs, with the boiler component only called upon in certain circumstances e.g. when it is exceptionally cold or renewable generation is very low. The evidence shows that the installation of a hybrid heating system today can reduce gas consumption by up to 80% and carbon emissions by almost 100% when using a tariff supplying low carbon electricity and entirely renewable gas³.
The decarbonisation credentials of hybrids don’t end there. Hybrid solutions can be very effective in encouraging a more gradual transition to fully electric heat pumps by allowing consumers to become familiar with the technology. Hybrid heating systems typically require far fewer changes in the home than a solely electric heat pump, so represent a stepping stone for consumers to gradually get used to heat pump technology. In this respect, hybrids and electric heat pumps have the real potential of being complementary, with the former leading to a potential widespread roll-out of the latter.
That’s not to say that that hybrids will only ever be transitory; there’s no reason why they can’t be an enduring solution. As already touched on, if a green gas such as biomethane, or a blend of biomethane and low carbon hydrogen, is consumed in the boiler then the whole hybrid system would be Net Zero compliant, irrespective of whether the gas boiler or electric heat pump element is running. In this scenario, we could effectively and efficiently heat a significant number of homes while positively contributing to our ambitious national climate targets. Based on research conducted by the Green Gas Taskforce, there is ample potential for sustainable biomethane production in GB to heat every single home in the country with a hybrid heat pump by 2050⁴.
Crucially, this can all come at a lower cost to the consumer (compared to solely using electric heat pumps) and brings minimal disruption to people’s lives. Unlike 100% electric heat pumps, customers upgrading to hybrid systems are not required to go through the common prerequisite steps of upsizing radiators, changing pipework or finding space for hot water storage units, which all come at a cost. Hybrids themselves are relatively cheap to install, with the electric heat pump able to simply be plumbed into an existing gas boiler heating system.
The potential of hybrids to lower bills has been recently demonstrated in a trailblazing trial carried out by Intergas Heating Ltd in the Netherlands⁵. In a trial of 174 homes across the course of two winters, Intergas and their trial partners found a 75% average reduction in gas use and average annual savings of €1000 per household from optimising based on price between use of electricity and gas. With no major modifications required to the properties taking part, these findings represent a significant saving for households at a time where energy bill concerns are higher than they have ever been. While this was only a trial, and one based on different market conditions in the Netherlands than the UK, the findings significantly add to the evidence base which should inform our policymaking on heat decarbonisation.
Adoption of hybrid heating systems would also bolster energy security by taking additional pressure off the electricity grid. The results of the Freedom Project trial⁶ showed that, compared to full electric heat pump systems, using hybrid heating systems saved a cumulative reinforcement cost for the South Wales electricity distribution system of around £1.3bn by 2050. This demonstrates how hybrids can work within the existing DNO capacity limits whilst still allowing a significant proportion of heat to be electrified.
As well as avoiding system costs from full-electrification, hybrid systems offer an aggregated fast frequency response (turn down) flexibility service. By having the ability to switch between clean power and green gas, power demand for heat can be almost entirely removed from the electricity system in about a second for an indefinite period to help prevent power cuts and system losses which require a black start.
What next? Spreading the benefits of hybrid heating systems
Whether it comes to decarbonisation, minimising costs and disruption to the customer or managing grid capacity, the case for hybrids is immensely compelling.
That is why it is disappointing that they have historically not qualified for the Boiler Upgrade Scheme (BUS). A Department for Energy Security and Net Zero consultation on the future of the BUS, which provides grants for heating systems in homes and non-domestic buildings, recently closed. This gave us at Future Energy Networks (FEN) and the wider industry the opportunity to set-out why hybrid heating systems should be included in the scheme as soon as possible.
At the heart of the government’s energy strategy are commitments to Net Zero, lower consumer costs and enhanced energy security. By embracing the transformational power of hybrid heating systems, government ministers can accelerate progress on all three counts.
[1] According to DESNZ, in 2023 buildings and product uses were ‘estimated to have been responsible for 20% of greenhouse gas emissions in the UK. Of these emissions, 65% were from fuel combustion in residential buildings, 17% in commercial buildings, 11% in public sector buildings and 7% were other buildings and product use emissions. https://assets.publishing.service.gov.uk/media/67a30e4f7da1f1ac64e5feb1/2023-final-greenhouse-gas-emissions-statistical-release.pdf
[2] According to the CCC, 80% of homes will be heated by a heat pump by 2050, with the rest served by heat networks or direct electrification. https://www.theccc.org.uk/publication/the-seventh-carbon-budget/#post-49721-_Toc187753760
[3] See Cadent’s ‘The scope for using hybrid systems in home heating’ report. https://cadentgas.com/getmedia/37a587e1-3b0b-437c-bc1f-82cabaf78fe3/The-Future-of-the-Gas-Network_Recommendations-for-Hybrid-Heating_210mm-x-297mm_V4.pdf
[4] The Green Gas Taskforce has calculated that sufficient feedstock can be available to deliver up to 50 TWh of domestic biomethane production by 2030, and up to 120 TWh by 2050. 120 TWh is enough energy to heat every home in the country if combined with electricity through a hybrid heat pump. https://greengastaskforce.co.uk/unlocking-the-future-of-biomethane/
[5] See Intergas’s ‘Final Report Demonstration Project Hybrid Heat Pumps’. https://verenigingduurzamewarmte.nl/wp-content/uploads/sites/10/2025/05/Final-Report-Demonstration-Project-Hybrid-Heat-Pumps-2.pdf
[6] The Freedom Project aimed to better understand if hybrid heating systems are technically capable, affordable and attractive to customers as a way of heating homes. https://www.nationalgrid.co.uk/projects/freedom