The Boiler Upgrade Scheme has a fixed annual budget, and applications are processed in order of receipt
The Boiler Upgrade Scheme (BUS) is not an open-ended entitlement; it operates with a finite annual budget set by the Department for Energy Security and Net Zero (DESNZ). Applications from MCS-certified installers are processed sequentially. Once the annual budget for a given financial year is fully allocated, no further vouchers are issued until the next funding round opens (DESNZ, Boiler Upgrade Scheme: Scheme Guidance, 2026).
The direct answer is that the boiler upgrade scheme funding limit means the grant is first come, first served within each financial year. Once the annual budget is exhausted, applications are rejected until the next financial year begins on 1 April.
The current funding limit for the 2026/27 financial year is £150 million, with a £7,500 cap per property
The total annual budget for the BUS in 2026/27 is £150 million, as confirmed by the DESNZ annual budget statement (DESNZ, Boiler Upgrade Scheme: Grant Amounts, 2026). Each eligible property can receive up to £7,500 for an air source heat pump or a ground source heat pump. The £7,500 amount is a fixed grant, not a percentage of installation cost. This means the grant covers a flat sum regardless of the total installation price, which can vary widely depending on house size and existing heating system.
Quick numbers BUS budget, grant amounts, and claim windows for 2026/27
| Funding element | Amount | Source |
|---|---|---|
| Total annual budget | £150 million | DESNZ, 2026 |
| Grant per property for air source heat pump | £7,500 | DESNZ, 2026 |
| Grant per property for ground source heat pump | £7,500 | DESNZ, 2026 |
| Typical claim window | 90 days from voucher issue | Ofgem, 2026 |
| Annual budget start date | 1 April 2026 | DESNZ, 2026 |
Only homeowners with a valid MCS-certified installer application are eligible to access the fund
Eligibility is strictly tied to the installer, not the homeowner directly. The installer must submit the application on the homeowner’s behalf. The property must have a valid Energy Performance Certificate (EPC) with no outstanding recommendations for loft or cavity wall insulation (GOV.UK, Boiler Upgrade Scheme: Eligibility, 2026). This means if your EPC recommends loft insulation and you have not installed it, the application will be rejected. The installer must also hold current Microgeneration Certification Scheme (MCS) certification for the heat pump product being installed.
The direct answer the boiler upgrade scheme funding limit means the grant is first come, first served until the annual budget runs out
The BUS operates on a first-come, first-served basis within each financial year. Once the annual budget is exhausted, no new vouchers are issued until the next financial year’s budget opens (Ofgem, BUS Application Processing Policy, 2026). There is no waiting list or carry-over of unallocated funds from a previous year. If the budget runs out mid-year, you must wait until 1 April of the following year to reapply.
How to confirm your installer is MCS-certified and registered to apply for the BUS
Homeowners can verify an installer’s MCS status on the MCS Installer Database at mcscertified.com (MCS, MCS Installer Database, 2026). The installer must also be registered with TrustMark for consumer protection and must be on the BUS installer list maintained by Ofgem (TrustMark, Scheme Standards, 2026). If your installer is not MCS-certified or not on the Ofgem list, the application cannot proceed. Ask your installer for their MCS certificate number and check it against the database before agreeing to any work.
What happens if the BUS budget runs out before your application is processed
If the annual budget is fully allocated, your installer’s application will be rejected, and no voucher will be issued (DESNZ, Boiler Upgrade Scheme: Annual Budget Allocation, 2026). You can reapply when the next financial year’s budget opens on 1 April (for the 2027/28 cycle). There is no automatic rollover or priority for previously rejected applications. To improve your chances next time, ensure your EPC is up to date and all insulation recommendations are addressed before the new budget opens. how to check EPC recommendations for heat pump eligibility
