Boiler Upgrade Scheme (BUS): are you eligible, and how do you apply?

The Boiler Upgrade Scheme (BUS) pays a grant towards an air-source or ground-source heat pump in England and Wales, and — unlike ECO4 — there is no income or benefit test. But eligibility isn't automatic: your property has to meet specific rules on existing heating, build status and installer certification, and the grant itself is claimed for you rather than paid to you directly. This page walks through exactly who qualifies, what disqualifies a property, and the step-by-step process your installer follows to get the voucher issued and redeemed. For the current grant amounts, including the temporary £9,000 off-gas-grid uplift, see our 2026 grant-tier breakdown.

What is the Boiler Upgrade Scheme?

The BUS was introduced in April 2022 to encourage homeowners to replace gas and oil boilers with low-carbon heating. It is administered by Ofgem on behalf of the Department for Energy Security and Net Zero (DESNZ). The scheme is demand-led — if you meet the eligibility criteria and your installer has available voucher allocation, you can access it.

Grant levels as of mid-2026:

• Air-source heat pump (ASHP): £7,500 — £9,000 if the property is off the gas grid and currently heated by oil or LPG
• Ground-source heat pump (GSHP) or water-source heat pump: £7,500 — £9,000 under the same off-gas-grid oil/LPG uplift
• Biomass boiler: £5,000 (limited availability — only in rural areas off the gas grid)
• Air-to-air heat pump: £2,500 (residential properties only, eligible since 2025)

These figures were uplifted from the original launch amounts (£5,000 for ASHP, £6,000 for GSHP) in October 2023 to close the cost gap with gas boiler replacements. The latest change is a temporary £1,500 top-up, taking ASHP and GSHP grants to £9,000 (a 20% increase) for off-gas-grid properties currently heated by oil or LPG. It runs from 21 July 2026 to 31 March 2027 and does not apply to biomass or air-to-air installs, or to homes already connected to mains gas. For the full breakdown of every current tier, see our Boiler Upgrade Scheme 2026 grant guide.

Who qualifies?

The headline criteria are simple — no income test, any homeowner can apply — but the small print is where applications get rejected. Ofgem checks each of the following before a voucher is issued:

• Property type: Must be a domestic property in England or Wales (Scotland and Northern Ireland have separate programmes). Small businesses and self-builds also qualify in some cases.
• Existing heating: You must be replacing a system currently heated by mains gas, oil or LPG (or, for the air-to-air and heat-battery categories, electric resistance heating). You cannot use BUS to upgrade a heat pump you already have, or a property with no fossil-fuel system to replace.
• New-build exclusion: Homes still under active construction by a developer do not qualify. A finished new-build that was fitted with a fossil-fuel boiler can be eligible. Self-builds can also qualify, but you'll typically need to show proof — such as title deeds — that the property was never owned by a business and wasn't built by a developer for onward sale.
• One grant per property: If a previous owner has already claimed a BUS voucher for the address, it cannot claim a second time, regardless of who owns it now.
• No minimum insulation requirement: Unlike ECO4, there is no mandatory EPC band. However, Ofgem requires your installer to confirm the heat pump is appropriately sized and that no significant energy-efficiency improvements are obviously needed first.
• Biomass has extra conditions: On top of the standard rules, a biomass boiler installation must be off the gas grid, in a rural area, and the property needs an emissions certificate. Self-builds are not eligible for the biomass tier.
• MCS-certified installer: The heat pump must be installed by an installer certified by the Microgeneration Certification Scheme (MCS) for that specific technology — not every MCS-certified installer covers every category, and air-to-air in particular is a smaller specialism than air-to-water.
• No income test: BUS is open to any homeowner regardless of income or benefits received. This is the key difference from ECO4.

BUS is not available in Scotland (where Home Energy Scotland interest-free loans cover heat pumps) or Northern Ireland (which has its own NISEP programme).

Why it matters for solar buyers

BUS is relevant to solar buyers for two reasons:

1. Solar + heat pump is a strong combination. A heat pump driven by solar electricity significantly reduces your operating cost, since you are heating with effectively free energy during the day. A 4kWp solar array and an ASHP is one of the most common retrofit combinations for households trying to eliminate gas.
2. A heat pump unlocks ECO4 solar panels. Under ECO4, solar PV is only fundable as a heating measure — meaning your home must have, or be getting, a heat pump or electric heating. If you are eligible for ECO4 (lower income, qualifying EPC band) and you are also installing a heat pump, you may be able to stack ECO4-funded solar on top of your BUS-funded heat pump. Confirm stacking eligibility with your installer, as scheme rules can interact.

How to apply, step by step

You do not apply to Ofgem yourself, and BUS never pays you directly. The installer runs the application on your behalf, and the grant is deducted from your invoice before you pay anything:

1. Get quotes from MCS-certified heat pump installers who are registered to claim BUS vouchers. Not every MCS installer participates in BUS, and not every participating installer is registered for every technology tier — confirm this explicitly when getting quotes.
2. The installer surveys your property to size the heat pump correctly and confirm it meets the eligibility rules above (existing fossil-fuel system, no prior voucher on the property, new-build/self-build documentation if applicable). Your quote should already show the grant amount deducted.
3. The installer raises the voucher application with Ofgem on your behalf, submitting the property and installation details electronically.
4. Ofgem issues a voucher, valid for three months. If the installation slips past the voucher's expiry, the installer has to reapply — factor this into your booking timeline if you're choosing an installer with a long lead time.
5. The installer commissions and installs the system within 120 days of the voucher being issued. This installation window is a hard Ofgem rule, not a guideline.
6. The installer redeems the voucher after installation and confirms the work with Ofgem. The grant amount is deducted from your final invoice — you only ever pay the balance.

You can find registered BUS installers via the GOV.UK BUS page or the MCS installer directory.

What BUS does not cover

• Solar PV panels (covered separately by ECO4 or Warm Homes Plan)
• Battery storage
• Underfloor heating or radiator upgrades (these are additional costs the homeowner bears)
• Properties in Scotland or Northern Ireland