Labour should increase support for hybrid heating solutions to lower rural emissions affordably
Duncan Carter, Corporate Affairs Manager
| Calor Gas
A recently closed consultation on expanding the number of technologies supported by the Boiler Upgrade Scheme (BUS) fails to include proven low carbon hybrid heat pumps that are well suited to helping many rural, off-gas grid households transition to lower carbon heating systems affordably and with minimal disruption.
The government’s intention to expand BUS is further acknowledgment that heat pumps will not be suitable for every home, and alternative low carbon heating technologies are required. Calor fully supports the government’s intention to expand the BUS to include multiple heating technologies and recognise the innovation taking place across the industry.
We believe the future strategy for decarbonising domestic heating must support homes off the gas grid that are unsuitable for heat pumps and therefore include Renewable Liquid Gases (RLGs) such as bioLPG (or biopropane) – a low carbon, renewable and direct substitute for conventional LPG – as a supported tool for decarbonisation, both in standalone gas boilers and hybrid heat pump applications.
Despite the £10.2bn recommitted by Labour to the Warm Homes Plan, there remains a policy gap for rural homes. This is despite the government’s own analysis showing that about 20 per cent of rural homes won’t be suitable for air source heat pumps. The consultation on extending support to new technologies in the BUS is limited to air-to-air heat pumps and ‘heat batteries’. Hybrid heat pumps must be included in BUS, particularly when used in off-gas grid settings and this urgently needs to be addressed by the Warm Homes Plan.
DESNZ contends that supporting hybrids, which combine a heat pump alongside a gas boiler, will lock in continued fossil fuel use. However, many off-gas grid homes have high heat demand, which can make them unsuitable for using heat pumps alone without expensive and disruptive property retrofit. Hybrids offer a flexible solution that can reduce emissions and, importantly for consumers, household bills. When combined with RLGs, hybrids offer a long term, net zero compatible solution for many off-gas grid rural properties.
Unless the proposals are revised, households in off-gas grid communities may face a prohibitively large financial burden to retrofit their homes or face a greater risk of installing a heat pump that is unable to adequately heat their homes. Alternatively, such households could choose to avoid decarbonisation in favour of maintaining their existing, high carbon, heating systems.
The decision to give indicative support to heat batteries in the BUS over hybrid heat pumps is perplexing. We consider heat batteries to be an under-researched technology, with only one or two providers to the domestic heating market, and suggest further research is carried out to provide the required evidence to support their inclusion in BUS. For example, approximately 35 per cent of rural homes are expected to have an annual heat demand of over 12,000kWh1, making them unsuitable for certain heat battery technologies. Consideration of the environmental impact of the production and end of life recycling of the heat batteries is also required, as they incorporate dense phase change materials, which can be difficult to recycle.
Hybrid heat pumps have been popular in the Netherlands and in Scotland, with over 330 installed north of the border by the Energy Savings Trust’s (EST) Home Energy Scotland grant support scheme since 2023. In a disappointing move, this support was taken away earlier this year by the Scottish Government following advice from MCS relating to an update to the MCS Heat Pump Design Standard.
DESNZ is currently consulting on ‘raising product standards for space heating’ which sets out reasonable definitions of a hybrid heat pump, and minimum performance standards to protect consumers. Calor agrees with the proposed definition of hybrid heat pumps and we support the adjustment of the definition of a heat pump space heater. This will ensure hybrid heat pumps will be included in government policy, providing greater clarity for both installers and consumers, enabling hybrids to contribute to the decarbonisation of heat in the UK. A logical next step would be to support their uptake via the BUS.
To take one example from the EST, Helga and John, residents of a 1919–1944 bungalow in Anstruther, Fife, undertook significant energy efficiency upgrades to enhance their home's warmth and reduce running costs. Initially considering an air-to-air heat pump, they opted for an 8 kW Daikin Altherma hybrid air-to-water heat pump combined with a 31 kW LPG condensing boiler. This system intelligently switches between electricity and LPG based on real-time energy prices and outdoor temperatures, ensuring optimal efficiency.
These upgrades have made their home significantly warmer, more comfortable, and with significantly lower emissions, while accommodating John's elderly mother without the need for constant stove heating. The hybrid system's automated control system allows them to optimise based on variable energy prices, enabling the system to choose the most cost-effective heating method.
Government should take the opportunity via the current consultation on BUS and ahead of the Warm Homes Plan to commit to hybrid heat pumps and send a clear signal to the market, installers and households of their valuable role in decarbonising off-gas grid properties.
- Based on 2022 National Energy Efficiency Data-Framework consumption figures for Village, Hamlet & Isolated Dwellings (National Energy Efficiency Data-Framework (NEED) - GOV.UK)
