Boiler Upgrade Scheme 2026: Grant Amounts, Eligibility & How to Apply

The Boiler Upgrade Scheme (BUS) is the UK government's main grant for replacing a fossil-fuel boiler with a heat pump, and the figures genuinely do move — grant tiers, uplifts and eligibility details have all changed at least once since the scheme launched in April 2022. This is the up-to-date 2026 overview: current grant amounts by technology, exactly who qualifies, the new off-gas-grid uplift, and how the installer-led application actually works. If you already know you want an air source heat pump and are comparing brands, see our best air source heat pump UK roundup; if you're still weighing whether a heat pump makes financial sense at all, start with are heat pumps worth it in the UK.

What is the Boiler Upgrade Scheme?

BUS is a government grant administered by Ofgem on behalf of the Department for Energy Security and Net Zero (DESNZ). It pays a fixed voucher amount toward replacing a fossil-fuel heating system — gas, oil or LPG — with a heat pump or biomass boiler. Unlike the old means-tested ECO schemes, BUS has no income test: any homeowner, landlord or small business in England or Wales can apply, provided the property and installation meet the scheme rules.

The scheme sits under the wider Warm Homes Plan and is funded through to 2029/30. It is demand-led rather than a fixed annual pot per household — if you meet the criteria and your installer has voucher capacity, you can access it.

BUS grant amounts in 2026

These are the current grant tiers confirmed on GOV.UK and Ofgem's Boiler Upgrade Scheme guidance:

• Air source heat pump (air-to-water): £7,500
• Ground source or water source heat pump: £7,500
• Biomass boiler (off-gas-grid, rural properties only): £5,000
• Air-to-air heat pump (residential properties only): £2,500

Air-to-air systems became eligible for the first time in 2025 — before that, only hydronic (wet) heat pump systems qualified. If you're weighing an air-to-air system specifically, our air-to-air heat pump grant guide covers what these systems can and can't do (they don't provide domestic hot water) in more depth than fits here.

Heat batteries: confirmed grant, not yet claimable

A £2,500 BUS grant for heat batteries — insulated thermal-storage units that store heat rather than electricity — was confirmed as a new category in 2025, alongside air-to-air heat pumps. As of mid-2026, that grant is not yet claimable: MCS is still finalising the Thermal Energy Storage Systems (TESS) installation standard that installers need to certify against, and applications are expected to open once that standard comes into force, anticipated around winter 2026. If you're researching heat batteries now, our heat battery UK guide covers the technology and how to position yourself to claim the grant once applications open.

The 2026 off-gas-grid uplift

The biggest change for 2026 is a temporary top-up for off-gas-grid homes. If your property currently heats with oil, LPG or direct electric heating (no mains gas connection) and you're installing an air source or ground source heat pump, Ofgem's guidance confirms an additional £1,500 uplift on top of the standard £7,500 — taking the total to £9,000. This uplift runs from 21 July 2026 to 31 March 2027. It does not apply to biomass boilers or air-to-air systems, and it isn't available to homes already connected to the mains gas grid, however inconvenient their current heating.

Who is eligible?

The core rules, drawn from GOV.UK's BUS eligibility guidance:

• England and Wales only. Scotland has its own Home Energy Scotland loan and grant scheme; Northern Ireland's boiler replacement scheme has closed. If you're outside England and Wales, check the devolved-nation programme for your area rather than applying here.
• Replacing a fossil-fuel system. The property must currently be heated by oil, mains gas, LPG or, for the air-to-air/heat-battery categories, electric resistance heating. You can't use BUS to upgrade an existing low-carbon heating system.
• Most new-build properties are excluded. Homes still under active construction by a developer don't qualify. A finished new-build already 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 sale.
• Biomass has extra conditions. On top of the standard rules, a biomass boiler 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.
• One grant per property. If a previous owner has already claimed a BUS voucher for the property, it can't claim again.
• MCS-certified installer. The installer carrying out the work must be certified by the Microgeneration Certification Scheme (MCS) for the relevant technology — not every MCS-certified installer is set up for every category (air-to-air in particular is a smaller specialism than air-to-water).
• 120-day installation window. Once a voucher is issued, the installer must commission and install the system within 120 days.

There's no mandatory EPC band and no income or benefits test — that's the main thing that distinguishes BUS from the means-tested Warm Homes Local Grant and the closing ECO4 scheme. For the full picture of how BUS fits alongside those other routes, see our Warm Homes Plan guide.

How the grant is paid — you never see the money

BUS doesn't work like a rebate or a cashback claim. You don't apply to Ofgem yourself and you never receive a payment directly. Instead:

1. Get quotes from MCS-certified installers who are registered to claim BUS vouchers — confirm this explicitly, as not every MCS installer participates.
2. The installer surveys your property, sizes the system correctly, and gives you a final quote that already shows the grant amount deducted.
3. The installer applies for the voucher with Ofgem on your behalf once you've agreed to proceed. Ofgem issues a voucher, valid for three months.
4. The installer completes the work within the 120-day window and redeems the voucher directly with Ofgem after installation.
5. You pay the net amount — the grant is subtracted from your invoice before you ever see a bill. There's no separate claim form, no reimbursement wait, and no cheque in the post.

This installer-led structure is deliberate: it removes the risk of a homeowner paying full price and then failing to reclaim the grant. It does mean your choice of installer matters — get at least two quotes, and confirm in writing that the quoted price already reflects the voucher deduction before you sign anything.

Typical net cost after the grant

Full installed pricing varies a great deal by property size, radiator or emitter upgrades needed, and region, but as a rough steer: a full air-to-water heat pump installation (unit, hot water cylinder and labour) commonly runs £9,000–£15,000 before any grant for a typical 3–4 bedroom home. Deducting the standard £7,500 grant brings that down to roughly £1,500–£8,000; deducting the full £9,000 off-gas-grid grant during the 2026/27 uplift window can bring net cost close to zero on smaller, simpler jobs. Always ask for an itemised, on-site quote — a phone or online estimate can't account for pipework, cylinder, or electrical upgrade costs specific to your property. If you're weighing a heat pump against staying on gas, our ground source heat pump guide and best air source heat pump UK roundup both include worked running-cost comparisons.

What BUS doesn't cover

• Solar PV panels — these sit under separate routes (ECO4, the Warm Homes Local Grant, or the market with 0% VAT), not BUS.
• Battery storage.
• Radiator or underfloor heating upgrades beyond what's needed for the heat pump itself — these are additional costs you bear.
• Properties in Scotland or Northern Ireland.
• A second grant on a property that's already claimed one.

2026 changes at a glance

If you looked at BUS a year or two ago, here's what's actually different in 2026:

• Air-to-air heat pumps are eligible for the first time (£2,500, from 2025), a category that didn't exist at launch.
• Heat batteries have a confirmed £2,500 grant, but applications aren't open yet — expected around winter 2026 once MCS finalises the TESS installation standard.
• A new £1,500 off-gas-grid uplift runs 21 July 2026 to 31 March 2027, taking ASHP/GSHP grants to £9,000 for qualifying oil, LPG and off-grid-electric homes.
• The core £7,500 ASHP/GSHP and £5,000 biomass tiers are unchanged from the October 2023 uplift (which raised them from the original £5,000/£6,000 launch amounts).

Because these figures move roughly annually, always check GOV.UK's current BUS guidance or ask your installer to confirm the live grant amount before signing a quote — don't rely on a figure you saw in a previous year's article, including this one after its next update.