The Institution of Gas Engineers and Managers (IGEM) published its response to the government's Boiler Upgrade Scheme consultation, Part 1, in June 2025, covering proposals to stimulate heat pump demand and strengthen consumer protections1. The professional body, founded in 1863 and representing the gas industry, said it was broadly supportive of plans to let BUS-funded heat pumps be installed alongside other low carbon technologies, but opposed the exclusion of hybrid heating systems from the scheme1.
IGEM's central recommendation is that hybrids, which combine a heat pump with a gas boiler, be made eligible under the BUS, as they had been under the domestic Renewable Heat Incentive1. It argues the current £7,500 grant for a full heat pump system could be halved to deliver a hybrid system, or two heat pumps installed for the price of one1. The response cites evidence that hybrids are 30 to 40 per cent cheaper to install than standalone heat pumps (Eunomia, 2023), can meet up to 80 per cent of annual heat demand via the heat pump with the boiler used only at peak demand (Freedom Project, 2018; Gemserv, 2024), and can cut peak electricity demand by up to 50 per cent, avoiding £30 to £40 billion in network reinforcement costs (Imperial College London, 2021)1.
"We urge the government to adopt a technology-agnostic approach and include hybrid systems in the BUS."
On carbon, IGEM states that hybrid systems using natural gas can reduce emissions by up to 60 per cent today, rising to 80 per cent by 2030 as the electricity grid decarbonises (Cadent, 2025), and that with a 100 per cent renewable gas tariff and low carbon electricity they can deliver net zero heating today1. It says there is enough biomethane already connected, or in the process of connecting, for 1.2 million homes heated by a gas boiler, or around 6 million homes heated by a hybrid system1. The response also notes that up to 40 per cent of UK homes may be unsuitable for standalone heat pumps due to space or insulation constraints (Gemserv; Intergas; EUA), and that in the Netherlands hybrids account for 50 per cent of the heat pump market (Cadent, 2025)1.
On the consultation's third question, IGEM answered no to BUS grants for air-to-air heat pumps, saying members consider this may not be the best use of public funds, that the appliances are already affordable without subsidy, and that they typically lack hot water provision1. It said feedback from some members indicated air-to-air support is better suited to the Energy Company Obligation1.
| IGEM position | Consultation proposal |
|---|---|
| Hybrid heat pump and gas boiler systems eligible for BUS | Hybrids excluded |
| No BUS grant for air-to-air heat pumps | Grants proposed for air-to-air |
| Electric-only eligibility requirement removed | Electric-only requirement retained |
Why it matters for households
The BUS is the main grant route for replacing a fossil fuel heating system in England and Wales, so which technologies qualify determines what a household can claim for. IGEM's argument is that a hybrid, which keeps a gas boiler alongside a heat pump, would cost less to install and involve less disruption than a full heat pump conversion, because a hot water cylinder, insulation, radiator changes and microbore pipework replacement are often prerequisites for a standalone heat pump to run efficiently1. For a home that cannot accommodate those changes, or where the occupier does not want full electrification, hybrid eligibility would widen the options available under the scheme. The counter-position, that public money should support technologies needing help to scale, is the basis of IGEM's objection to air-to-air grants1. Whether hybrids are included is a decision for government, and no outcome has been reported.
What happens next
The consultation response was published in June 20251. The government's decision on the proposals, and any change to BUS eligibility rules, has not been reported.