James HarrisonThe UK Boiler Upgrade Scheme (BUS), administered by Ofgem on behalf of the UK government, offers grants of up to £7,500 to help homeowners in England and Wales replace fossil fuel boilers with low-carbon heat pumps. As of 2026, confirmed grant amounts are £7,500 for air source heat pumps (ASHPs), £7,500 for ground source and water source heat pumps (GSHPs/WSHPs), and £5,000 for biomass boilers in eligible rural, off-gas-grid properties. The entire application is handled by your installer — not you — making the process more straightforward than most expect. The scheme runs until March 2028.
What Is the Boiler Upgrade Scheme and Why Does It Matter in 2026?
The Boiler Upgrade Scheme (BUS) is a grant programme run by the UK's Department for Energy Security and Net Zero (DESNZ) and administered by Ofgem. It launched in April 2022 as the successor to the domestic Renewable Heat Incentive (RHI), and it funds the gap between the cost of a conventional gas boiler replacement and a low-carbon heat pump installation.
The scheme is central to the UK's Heat and Buildings Strategy, which targets the installation of 600,000 heat pumps per year by 2028. Low-carbon heating is unavoidable on the path to the UK's legally binding net-zero 2050 target, and the BUS is designed to make the upfront cost barrier manageable for ordinary homeowners.
Who Administers the BUS?
Ofgem — the Office of Gas and Electricity Markets — manages applications, issues vouchers, and processes installer claims. The funding comes from a government levy, and Ofgem's role is purely administrative: it validates applications and pays installers once installation is confirmed.
England and Wales Only
A critical point many homeowners miss: the BUS applies only in England and Wales. Scotland has its own support structure through Home Energy Scotland (0808 808 2282), which offers interest-free loans and cashback on heat pump installations. Northern Ireland operates the Renewable Heat Incentive (RHI) scheme separately. If you are based in Scotland or Northern Ireland, do not apply to the BUS — contact your devolved scheme administrator directly.
Grant Amounts: How Much Can You Receive in 2026?
The Boiler Upgrade Scheme provides a one-off capital grant, paid directly to your MCS-certified installer, which is deducted from your final invoice. You never handle the money yourself.
Current Confirmed Grant Levels
The current grant rates, which apply to installations completed under the BUS through to March 2028, are:
| Technology | Grant Amount | Eligibility Condition |
|---|---|---|
| Air Source Heat Pump (ASHP) | £7,500 | England or Wales, replacing fossil fuel system |
| Ground / Water Source Heat Pump (GSHP/WSHP) | £7,500 | England or Wales, replacing fossil fuel system |
| Biomass boiler | £5,000 | Rural property, no connection to gas grid |
These amounts were uplifted in October 2023 — from an original £5,000 (ASHP) and £6,000 (GSHP) — following lobbying by the Heat Pump Association and Renewable Energy Consumer Code (RECC) to better reflect real installation costs [DESNZ, October 2023].
What the Grant Does and Doesn't Cover
The grant contribution is applied against the full cost of supply and installation, including equipment, labour, pipework, commissioning, and removal of the old heating system. It does not cover:
- Upgrades to your hot water cylinder (often needed for ASHP compatibility)
- Underfloor heating installation or radiator upsizing (common where the existing system runs at high temperatures)
- Smart meter or electrical panel upgrades
Budget an additional £500–£2,500 for these ancillary works, depending on your property. A fully installed ASHP in a typical semi-detached home costs £10,000–£15,000 before the grant [Heat Pump Association, 2025], so the £7,500 contribution is significant but not total coverage.
Eligibility Requirements: Who Can Apply?
Eligibility is checked by both the property's characteristics and the applicant's status. Your MCS-certified installer will conduct a pre-installation assessment to confirm eligibility before submitting the grant application to Ofgem.
Property Requirements
Your property must be located in England or Wales, be a domestic dwelling or a small non-domestic property with a thermal output of up to 45 kW, and hold a valid Energy Performance Certificate (EPC) issued within the last 10 years. Critically, the EPC must carry no outstanding recommendations for loft insulation or cavity wall insulation — unless an exemption has been recorded on the EPC register (for example, if your loft is inaccessible, or if cavity wall insulation would cause damp).
If your EPC does flag insulation gaps, you must complete the recommended work first. The Green Homes Grant Local Authority Delivery (LAD) scheme or your energy supplier's ECO4 (Energy Company Obligation) scheme may fund this separately.
Heating System Requirements
The BUS grant is for replacement, not addition. You must be replacing a fossil fuel heating system — gas, oil, or LPG boiler, electric storage heaters, or solid fuel (coal, wood) systems. New-build properties are not eligible under the standard rules, with a narrow exception for self-build projects where the owner-occupier is replacing an interim heating system installed during construction.
Who Can Hold the Application
The grant application must be made by an MCS-certified installer on behalf of the property owner, private landlord, or custom self-builder. Social housing landlords are not eligible under the BUS (they access separate funding through the Social Housing Decarbonisation Fund).
Key takeaway: If your property is a listed building or in a conservation area, permitted development rules may restrict external heat pump equipment. Check with your local planning authority before commissioning installation.
How to Find an MCS-Certified Installer
The Microgeneration Certification Scheme (MCS) is the quality mark for small-scale renewable energy technology in the UK. Under the BUS rules, all installers must hold current MCS certification for the specific technology they are installing — an installer certified for solar panels cannot install a heat pump under BUS.
Using the MCS Installer Finder
The official search tool is available at mcscertified.com/find-an-installer. Enter your postcode and select your technology type (heat pump or biomass). The tool returns certified companies within your search radius, with contact details, years of certification, and technology specialisms.
As of 2026, there are approximately 2,000 MCS-certified heat pump installers in England and Wales [MCS, 2025]. Demand has grown significantly since the 2023 grant uplift, so lead times of 4–12 weeks for site survey and installation are common in busier regions.
Vetting Your Shortlist
Obtain at least three written quotes. When comparing, ask each installer:
- How many heat pump installations have you completed in properties similar to mine?
- Will you conduct a room-by-room heat loss calculation (to BS EN 12831)?
- Are radiator upgrades included in your quote, or quoted separately?
- What is the warranty period on the heat pump unit and on your labour?
- Who handles the BUS voucher application, and what is the expected timeline?
A reputable installer will size the heat pump to your property's specific heat demand — not simply replace a gas boiler of equivalent nominal output. Oversizing wastes energy; undersizing leaves the home cold.
Step-by-Step: How to Apply for the Boiler Upgrade Scheme
One of the BUS's most underappreciated features is that you do not submit the application yourself. The installer manages the entire process with Ofgem. Here is exactly how it works:
Before You Start: Check Your EPC
Step 1: Confirm your EPC is valid and insulation recommendations are resolved. Download your property's EPC from the GOV.UK EPC register. If it is more than 10 years old, or carries unresolved loft or cavity wall recommendations, address this before proceeding.
Step 2: Obtain quotes from at least three MCS-certified installers. Use the MCS Installer Finder (mcscertified.com). Each quote should include equipment cost, labour, commissioning, and confirmation that the installer will apply for the BUS voucher on your behalf.
The Application and Voucher Stage
Step 3: Sign a contract with your chosen installer. The installer then submits the BUS application to Ofgem's online portal on your behalf. You will need to sign a declaration confirming you own or have permission to upgrade the property.
Step 4: Ofgem issues a grant voucher. Ofgem typically issues a voucher within 5–10 working days of a successful application. The voucher specifies the grant amount and has a validity window: 3 months for air source heat pumps and 6 months for ground source heat pumps and biomass boilers. The installation must be completed and commissioned within this window.
Installation, Commissioning, and Payment
Step 5: Installation and commissioning. Your installer completes the work and generates an MCS installation certificate — a legal document proving the system was installed and commissioned to MCS standards.
Step 6: The installer redeems the voucher with Ofgem. The installer submits the MCS certificate and commissioning documents. Ofgem verifies compliance and transfers the grant to the installer. The grant amount is deducted from your invoice — you pay only the balance.
Step 7: Register with your energy supplier. Following installation, notify your electricity supplier so the heat pump is recorded on your meter profile. If you have solar PV, you can also register for the Smart Export Guarantee (SEG) to export surplus generation.
Is a Heat Pump Worth It Beyond the Grant?
The BUS grant significantly reduces the upfront cost barrier, but the long-term economics depend on your property's insulation standard, your usage pattern, and the relative cost of electricity versus gas.
Running Costs and Efficiency
A modern air source heat pump operates with a Seasonal Coefficient of Performance (SCOP) of 2.5–4.0, meaning it delivers 2.5–4 units of heat for every unit of electricity consumed [Energy Saving Trust, 2025]. At current UK energy prices, a well-insulated home switching from a gas combi boiler to an ASHP can expect running costs to be broadly comparable — sometimes lower, sometimes slightly higher — depending on the electricity-to-gas price ratio. As the UK grid decarbonises further (renewable generation was 43% of UK electricity in 2024 [National Grid ESO, 2024]), the carbon advantage of heat pumps over gas grows year on year regardless of running-cost comparisons.
Impact on Your EPC Rating
An EPC rating improvement is almost certain after switching from a gas or oil boiler to an ASHP. Higher EPC ratings (C and above) are increasingly tied to mortgage rates, future Minimum Energy Efficiency Standards (MEES) for rental properties, and buyer expectations. Properties rated F or G will face restrictions on rental from 2028 under proposed MEES amendments — upgrading now addresses multiple compliance obligations simultaneously.
Noise and Disruption
Modern outdoor heat pump units produce 40–48 dB(A) at 1 metre — roughly equivalent to a quiet conversation or a modern refrigerator. Permitted development rules in England require the unit to be at least 1 metre from a boundary and not on a wall or roof fronting a highway. Urban installations occasionally require planning permission; your installer will advise.
Frequently Asked Questions
Can homeowners in Scotland apply for the Boiler Upgrade Scheme?
No. The BUS is restricted to England and Wales. Scottish homeowners should contact Home Energy Scotland on 0808 808 2282, which offers interest-free loans (up to £15,000) and cashback grants for heat pump installation. Northern Ireland residents should contact the DAERA-administered Renewable Heat Incentive scheme.
My EPC has an insulation recommendation — does this block my application?
Yes, unless an exemption applies. If your EPC recommends loft insulation or cavity wall insulation, you must complete that work before a BUS application can proceed. Exemptions include properties where the cavity wall insulation would cause structural damage or damp (certified by a surveyor), or where loft access is impossible. Exemptions are recorded on the national EPC register. Contact your local authority or Citizens Advice for guidance on ECO4 or LAD funding for the insulation work itself.
Does the £7,500 grant cover the full cost of a heat pump?
Typically not. A full ASHP installation in a standard UK semi-detached house costs between £8,000 and £15,000 before the grant, depending on the property's size, existing radiator sizing, and whether a new hot water cylinder is required [Heat Pump Association, 2025]. The grant covers a substantial portion but leaves a homeowner contribution of £500–£7,500 in most cases.
How long does the installation take from application to completion?
The Ofgem voucher is usually issued within 5–10 working days of the installer submitting the application. The installation itself takes 1–3 days for an ASHP, and up to a week for a GSHP that requires ground loop trenching or borehole drilling. Allow 4–12 weeks total from your first installer contact to a commissioned system, accounting for installer availability and equipment lead times.
Can I switch from a combi boiler to a heat pump without major home modifications?
Many properties can switch with relatively modest modifications, but some upgrades are usually necessary. Combi boilers typically run radiator circuits at 70–80°C flow temperatures; heat pumps work most efficiently at 35–55°C, which means your existing radiators may need upsizing (or underfloor heating installed) to compensate. You will also need a hot water storage cylinder, since heat pumps cannot provide instantaneous hot water as a combi does. Your installer's heat loss survey will identify exactly what is needed for your property.
Disclaimer: The information on this page is provided for general guidance only and does not constitute financial, energy, or regulatory advice. Grant amounts, eligibility criteria, and application processes for the Boiler Upgrade Scheme are subject to government review and may change. Always verify the latest details directly with Ofgem's BUS guidance pages before committing to an installation.
