Boiler Upgrade Scheme (BUS) UK 2026: Full Guide

The Boiler Upgrade Scheme (BUS) is the UK government's flagship grant scheme for heat pumps and biomass boilers in England and Wales. It launched in May 2022 and has been extended, expanded and revised several times since. The most recent revision (V5, effective 28 April 2026) extended the scheme to 2030 and added air-to-air heat pumps to the eligible list.

What you can get

How the grant works

1. You get a quote from an MCS-certified installer
2. The installer designs the system to MCS standards (heat-loss calc, emitter sizing, cylinder)
3. The quote shows the grant deducted directly from the total
4. You sign the quote and pay any deposit on the net amount
5. The installer applies for a voucher via Ofgem
6. Ofgem emails you to confirm consent and eligibility
7. Voucher approved (typically 2–4 weeks)
8. Install happens — 2–5 days on site for a standard ASHP retrofit
9. Installer redeems the voucher within 120 days of the MCS commissioning date
10. Ofgem conducts final eligibility checks against the MCS certificate

You don't deal with Ofgem directly. The grant comes off your bill at the point of sale — you only pay the balance.

Who's eligible

• You own the property in England or Wales
• Homeowners, private landlords, small businesses, custom and self-builders all qualify
• You're replacing a fossil-fuel or direct-electric system — gas, oil, LPG, coal, electric heating (storage, panel, electric boiler)
• The installer and product are both MCS-certified (or under an approved equivalent scheme)
• You haven't previously received public funding for the same heat pump installation

Who's not eligible

• New-build properties — unless they're genuine self-builds (built primarily using the labour and resources of the first owner)
• Social housing — including council tenancies, housing association tenancies, shared ownership. These have separate routes (Warm Homes: Social Housing Fund).
• Hybrid systems — a heat pump paired with a new gas/oil/LPG boiler does not qualify. BUS is for full replacement of the fossil-fuel system, not supplementation.
• Scotland — separate scheme: Home Energy Scotland
• Northern Ireland — separate arrangements

V5 changes (effective 28 April 2026)

The April 2026 update made three significant changes:

• Mandatory EPC requirement removed — you no longer need a valid EPC with no outstanding loft/cavity recommendations to apply. (Insulation is still worth doing on its own merits.)
• Air-to-air heat pumps added at a £2,500 grant tier (residential only) — recognising that some property types are better suited to A2A than to a wet system retrofit
• Scheme extended to 2030 as part of the Warm Homes Plan funding envelope

The April 2026 update also signalled the upcoming addition of heat batteries (£2,500) once product/design/installation standards are finalised, and the £9,000 oil/LPG uplift from July 2026.

Scheme funding and longevity

• BUS budget for 2026–27: £400 million
• Total BUS funding 2026/27–2029/30: £2,392 million
• Scheme extension confirmed to 2030 under V5
• Average BUS-claimed install (Oct–Dec 2025): £13,431 for an 8.4 kW system

What to look for in a BUS-compliant quote

• Itemised quote with the grant deducted as a clear line
• MCS-certified installer (look up at mcscertified.com)
• MCS-listed product (heat pump model)
• Room-by-room heat loss calculation
• Design flow temperature stated (35°C, 45°C or 50°C ideal; 55°C+ is a warning sign)
• Cylinder specification with coil rating (2.5–3.5 m²)
• Estimated SPF disclosed using the MCS 031 methodology
• MCS 020(a) sound assessment (mandatory from 28 May 2026)

Common questions

Can I combine BUS with other schemes?

Not for the same measure (e.g. you can't claim BUS and ECO4 for the same heat pump). But you can stack: BUS for the heat pump and ECO4 (separately) for insulation if eligible.

What if I've already had a BUS voucher for this property?

You can't claim a second BUS voucher for the same property. The scheme is one-per-property.

How long does the voucher take?

Typically 2–4 weeks from installer application to Ofgem approval. Once issued, vouchers are valid for 6 months.

What about Scotland?

Scotland operates the Home Energy Scotland Grant & Loan, which offers up to £7,500 grant plus an optional interest-free loan up to £7,500. Rural/island uplift adds £1,500 to the grant. Different eligibility rules apply.

Is there a means test?

No — BUS is not means-tested. It's available to any qualifying homeowner regardless of income. (Income-tested schemes are ECO4 and Warm Homes: Local Grant, both separate.)

What happens if my BUS application gets rejected?

Rejections are rare for properties that meet the eligibility criteria. If you're refused, Ofgem will explain why — usually it's because the property is a new build, social housing, or has already received public funding for the same measure. Ask your installer to escalate via Ofgem's dispute process if you think the decision is wrong.