The Boiler Upgrade Scheme: Grants for Heat Pumps and Biomass

The Boiler Upgrade Scheme (BUS) is the UK Government's grant for replacing fossil fuel heating with a heat pump or, in limited circumstances, a biomass boiler. It provides upfront capital grants of up to £7,500 towards an air-to-water, ground source or water source heat pump, £9,000 for eligible off-gas-grid homes heated by oil or LPG, and £5,000 towards a biomass boiler¹. The scheme covers England and Wales only, is administered by Ofgem, and applications are made by an MCS-certified installer on the property owner's behalf, never by the householder directly¹. It opened on 23 May 2022 and, as of 28 April 2026, has been extended to 2030, with applications closing on 30 December 2029 at 11:59pm³.

The grant is not a cheque. It is a discount the installer deducts from the quote before any payment is made by the property owner, and the installer then claims the money back from Ofgem⁴. That single design choice shapes everything about how the scheme works in practice, from the two-stage voucher process to the audits that can follow a payment.

About the scheme and what it funds

The Boiler Upgrade Scheme provides grants to assist with the installation costs of low carbon heating⁶. Its purpose is to support the decarbonisation of homes and small and medium non-domestic buildings in England and Wales by helping property owners replace existing fossil fuel heating systems with heat pumps and, in limited circumstances, biomass boilers². The scheme launched on 23 May 2022³.

The scheme was originally designed as a £450 million, three-year scheme⁸, with an initial budget of £150 million per financial year for 2022 to 2025⁴. That framing has since been overtaken by events: the budget has been increased in later years, the grant values were raised, and the scheme has been extended to 2030⁴. The government's wider heat and buildings policy treats the scheme as one of the delivery mechanisms for cutting carbon from buildings, alongside regulation and other funding programmes⁹.

Two boundaries define the scheme's reach. First, it is territorial: only properties located in England and Wales are eligible for BUS funding¹⁰. Scotland and Northern Ireland run their own arrangements, and households there should look to the home energy grants in Scotland and home energy grants in Northern Ireland instead. Second, it is a replacement scheme: the installation must replace an existing heating system that runs on fossil fuels or electricity, with existing heat pumps excluded¹¹. It is not a fund for new-build heating, with a narrow exception for self-builds.

Grant values: £7,500 standard, £9,000 off gas grid, £5,000 for biomass

The headline figures are set out in the approved grant categories and values notice issued under Regulation 13 of the Boiler Upgrade Scheme (England and Wales) Regulations 2022¹². The current values are:

The uplifted £9,000 grant deserves particular attention because it is time-limited. From 21 July 2026, eligible off-gas-grid properties can apply for the uplifted grant of £9,000 towards an air-to-water or ground source heat pump, where the property is not fuelled by mains gas and the heating system being replaced was fuelled by oil or liquefied petroleum gas (LPG)⁴. The uplifted value is in place only until 31 March 2027⁴. Properties that do not qualify for the uplift may still be eligible for the standard £7,500⁴.

An air-to-water heat pump installed in an off-gas-grid property that is replacing any other fossil fuel heating system is an approved grant category in its own right¹². The grant values shown above apply to applications properly made on or after 28 April 2026 under the current guidance¹¹. For a fuller breakdown of what each figure covers, see how much the Boiler Upgrade Scheme grant is.

Qualifying technologies and those excluded

The eligible technologies are air-to-water heat pumps, air-to-air heat pumps, ground source heat pumps (including water source heat pumps and shared ground loops), and biomass boilers⁴. Official statistics group these as air source heat pumps, ground source heat pumps, ground source heat pumps with shared ground loops and, in some circumstances, biomass boilers¹³. Exhaust air-to-water heat pumps are eligible for the £7,500 grant¹¹.

What does not qualify matters just as much. There is no grant for a hybrid heat pump system, for example a combination of a gas boiler and an air source heat pump¹⁴. The BUS-funded system must fully replace the property's existing fossil fuel or electric heating system, except where supplementary heating appliances are permitted¹¹. More detail is on the page do hybrid heat pumps qualify for the Boiler Upgrade Scheme?.

Each technology also carries technical conditions. Air-to-water and ground source heat pumps must achieve an in situ seasonal coefficient of performance (SCOP) of at least 2.8⁴. Capacity limits apply: 45 kWth for an individual heat pump system, 70 kWth for a multi heat pump system, and 300 kWth total for shared ground loop systems, with each connected heat pump not exceeding 45 kWth⁴. All heating systems installed under the scheme must meet the relevant MCS standards approved and published by the Secretary of State⁴.

Biomass is the most tightly restricted technology. Biomass boilers may only be installed in properties in rural areas, the maximum permitted capacity for an individual biomass boiler system is 45 kWth, and the emissions certificate must show particulate matter not exceeding 30g/GJ and NOx not exceeding 150 g/GJ net heat input⁴. The requirements are covered in more detail under Boiler Upgrade Scheme requirements for biomass boilers.

Who qualifies and eligible homes

The scheme is targeted at domestic and non-domestic properties in England and Wales, and self-build properties are eligible⁹. The core retrofit rule is that the previous heating system being replaced must have been either a fossil fuel-based system (such as gas, oil or LPG) or an electric heating system that does not include a heat pump⁴. A property will not be eligible if a previous BUS grant has already been received for installing a heat pump or biomass boiler at the same address⁴.

New properties are not eligible, with the exception of certain self-builds¹⁵. An eligible self-build is one built mainly using the labour or resources of the first owner¹⁶, and self-build properties are only eligible for BUS funding for heat pumps, not biomass⁴.

The Energy Performance Certificate position changed recently. From 28 April 2026, properties are no longer required to have a valid EPC to apply for the scheme⁴. Earlier rules required a valid EPC no more than 10 years old, with the certificate number provided at application¹¹, and the government has stated an intention to relax the EPC requirement further from 2026/27 onwards, adopting a hybrid model¹⁸. The grant listing still describes the EPC requirement as part of the scheme's conditions¹, so the position depends on when an application is properly made.

Social housing is excluded. Properties classed as social housing are not eligible for BUS funding, and that includes shared ownership properties¹⁰. Right to Buy properties may become eligible once they are privately owned¹⁹. Support for decarbonising social housing runs instead through the Social Housing Decarbonisation Fund in England and the Optimised Retrofit Programme in Wales¹⁷. The position is explained further under can social housing get Boiler Upgrade Scheme grants?.

When a property owner consents to an application, they confirm their full name, key project details, ownership, consent to the application, that they will own the system on completion, that the property is not social housing, and that they have not received other support from public funds or government schemes, such as the Energy Company Obligation, towards the system's costs¹⁷. The full eligibility rules are set out on the Boiler Upgrade Scheme eligibility page.

The application process: from voucher to redemption

The scheme is installer-led, and a property owner cannot apply themselves¹⁰. The installer applies for the grant on the property owner's behalf, discounts the grant from the invoice, applies to Ofgem for a grant voucher, and redeems the voucher after installation and commissioning¹. Only installers certified by the Microgeneration Certification Scheme (MCS) can apply for and redeem vouchers²⁰, a point covered further under do I need an MCS-certified installer to get a heat pump grant?.

The grant application has two stages: the voucher application and the voucher redemption application⁴. In outline:

1. The installer submits a voucher application to Ofgem on the property owner's behalf²¹.
2. Ofgem issues a voucher, with a validity period that depends on the technology⁴.
3. The installation is carried out and commissioned.
4. The installer submits a voucher redemption application²¹.
5. Once Ofgem has established that the remaining eligibility requirements have been met, the grant payment is made to the installer²².

A voucher application is only considered "properly made" once Ofgem has all the necessary information to assess eligibility and the property owner has provided consent and identity verification¹¹. Vouchers carry different validity periods: 6 months for ground source heat pumps and 3 months for biomass boilers⁴. Validity periods cannot be extended under any circumstances¹¹.

Applications are normally made before installation, but a retrospective route exists. Installers may apply for a voucher after the installation has been commissioned, provided the application is properly made within 120 days of the commissioning date¹⁰. Doing so carries additional risk for both the property owner and the installer, because the work is already complete before anyone knows whether the voucher will be granted¹⁷. Ofgem may grant an extension to the 120-day commissioning rule where the time taken to reach certain administrative decisions is likely to result in the period being exceeded for a re-application¹¹.

Installers must retain a copy of any information relied upon for voucher applications and redemptions for six years¹⁷, and Ofgem can conduct site or desk audits at any point after a BUS application, including after grant payment¹⁶. The step-by-step detail is on the how the Boiler Upgrade Scheme application works page.

The grant comes as a discount rather than cash

The grant is applied upfront as a discount to the cost of the installation. The property owner does not receive the grant directly: it is paid to the installer¹⁰. Installers must deduct the full BUS grant value from the quote before any payment is made by the property owner⁴. This has been the expectation since the scheme's launch, when installers were expected to discount the value of the grant from the total cost paid by the property owner and include this in their quote⁹.

In practical terms, a householder should expect the grant to appear as a line in the installer's quote, reducing the amount payable, with the installer recovering that sum from Ofgem at the redemption stage. The householder never handles the grant money. This is also why the scheme is described in official statistics as providing upfront capital grants²⁴: the capital arrives at the point of purchase, not as a reimbursement afterwards.

The one thing to watch is that the discount must be the full grant value. The guidance is unambiguous on this point, and a quote that does not pass the whole grant through to the customer does not meet the scheme's rules⁴.

Funding limits, quarterly caps and one grant per home

The scheme's budget is allocated by financial year, with quarterly voucher caps at the start of each quarter, beginning 1 April, 1 July, 1 October and 1 January¹¹. Vouchers are issued on a first come, first served basis, to applicants who meet the eligibility requirements, until the budget cap for the financial year is reached²⁵.

The budget has grown well beyond the original £150 million a year. In Scheme Year 4 (April 2025 to March 2026) the budget was £295,000,000, of which £185,500,000 had been allocated and £109,500,000 remained at the time of the Issue 14 quarterly report, published 26 November 2025²¹. In the first year, £50,999,000 was allocated from the original £150 million Year 1 budget between the scheme launch on 23 May 2022 and 31 March 2023¹⁵. Unspent budget is not carried over to the next scheme year²², which is why the quarterly caps matter: money not used within the year is lost to the scheme.

Only one voucher can be redeemed per property⁴, and only one grant is available per property¹⁴. A property that has already received a BUS grant for a heat pump or biomass boiler cannot receive another⁴.

Secondary heating and items that may remain

From 28 April 2026, BUS heat pumps can be installed alongside supplementary heating appliances, provided those appliances are not fossil fuel based⁴. This is a significant change to the scheme's earlier position, in which the BUS-funded system had to fully replace the existing heating system with nothing left alongside it.

The rules differ by technology. A biomass boiler may be retained or installed alongside a BUS-funded heat pump as supplementary heating, but it cannot be used to meet the heating demand requirement¹⁹. Biomass boilers funded through BUS themselves cannot be installed alongside supplementary heating appliances¹¹. The heat pump must be sized to meet the full space heating demand, either standalone or in combination with a supplementary appliance, with the key constraint that the BUS-funded heat pump must still be sufficient on its own for space heating¹⁹.

What this means for a household is that a heat pump grant no longer forces the removal of every other heating appliance in the house, as long as what remains is not fossil fuel based and the heat pump could carry the space heating load alone. A retained gas boiler, by contrast, would take the installation outside the rules, which is the same boundary that excludes hybrid systems from the grant¹⁴.

Scheme boundaries and related measures

The scheme has been extended to 2030⁴, and the closing date for applications is 30 December 2029 at 11:59pm¹. The government has said that changes to the scheme will continue to be introduced via scheme regulations when parliamentary time allows, including the planned relaxation of the EPC requirement from 2026/27 onwards¹⁸.

Ofgem is required to publish quarterly and annual reports on its website, and aims to publish monthly operational updates⁴. Annual reports are published on 31 July each year, covering the preceding 12-month period ending 31 March¹⁷. The monthly scheme update currently covers the period from 23 May 2022 to 30 September 2026²⁶, and the Issue 17 quarterly report covers 1 May 2026 to 31 July 2026²⁴.

The scheme does not stand alone. Funding from BUS and the Energy Company Obligation cannot be blended for the same measure or be included within an ECO4 project²⁷, a boundary explored in Boiler Upgrade Scheme or ECO4 for a heat pump? and on the ECO4 page. Households comparing the two routes should also read Boiler Upgrade Scheme vs ECO4. The wider landscape of support, including schemes that have already closed, is set out in the guide to home energy grants and schemes in the UK.

Implications for your household's energy self-sufficiency

A BUS-funded heat pump removes a home's dependence on delivered fossil fuels: no gas boiler, no oil or LPG deliveries, and no exposure to the fossil fuel market for heating. For off-gas-grid homes heated by oil or LPG, the uplifted £9,000 grant is aimed squarely at exactly that dependence⁴. A biomass boiler, where it qualifies, shifts the fuel to wood, which a household can source domestically.

What remains is electricity. A heat pump ties the home's heating to the electricity grid and to whatever a household pays for electricity, so the scheme buys independence from fossil fuels, not from the grid or from energy suppliers. That makes the electricity tariff and, over time, the grid's decarbonisation the deciding factors in whether the switch pays off. Households wanting to push further towards self-sufficiency often look at generation and storage alongside a heat pump, covered in grants and funding for solar panels and grants and funding for home battery storage.

The scheme's own limits also shape the outcome. One grant per property means one shot at the subsidy¹⁴. The first come, first served budget and the absence of carry-over mean the grant is available only while the money lasts²⁵. And the closing date of 30 December 2029¹ means the subsidy is a fixed window, not a permanent entitlement. Within those limits, the scheme is currently the largest single grant most households in England and Wales can get towards taking their heating off fossil fuels.