Boiler Upgrade Scheme voucher process

Scheme rules, grant amounts and process details were checked on 22 July 2026. They are a dated snapshot of the rules then in force.

The Boiler Upgrade Scheme (BUS) pays a fixed grant towards replacing a fossil fuel heating system with a heat pump or biomass boiler in England and Wales. Ofgem administers the scheme, processing the applications, issuing the vouchers and making the payments, while policy sits with the Department for Energy Security and Net Zero (DESNZ). The grant does not go to the homeowner as cash. It runs through the installer as an application to Ofgem and reaches the homeowner as a discount on the installed price. Scotland runs its own schemes and Northern Ireland’s Boiler Replacement Scheme is closed. Each property can receive one grant.

The scheme launched in May 2022 and has since been extended, with funding allocated through the 2029 to 2030 financial year. The amount depends on the technology, from £2,500 up to £7,500, with a temporary £9,000 grant for qualifying off-gas-grid homes replacing oil or liquefied petroleum gas (LPG) heating. The higher rate applies to applications properly made from 21 July 2026 to 31 March 2027. The amounts and their conditions are set out in the technology categories entry.

The application runs through the installer

Only an installer can apply for a BUS grant. The installer has to be certified by the MCS for the technology being fitted, and three things happen before any application is submitted:

• The installer advises whether the proposed installation is eligible for a grant.
• They agree a quote that shows the grant value as a deduction from the price.
• Both sides agree that the installer will submit the voucher application to Ofgem on the property owner’s behalf.

A homeowner cannot lodge the application directly. The choice of an eligible, MCS-certified installer therefore comes before the paperwork.

The consent email and the 14-day deadline

Once the installer submits the application, Ofgem emails the property owner to confirm two things: that they consent to the installer applying on their behalf and that they meet the eligibility criteria. The owner has 14 calendar days to respond. If Ofgem does not receive the confirmation in time, it may reject the application.

Consent is permission to apply, not a commitment to use that installer. The commercial contract between owner and installer is arranged separately. If more than one installer has applied for the same property, the owner can confirm consent to only one, and Ofgem rejects the others. Consent given by mistake can be corrected by contacting Ofgem at BUS.Application@ofgem.gov.uk. Where Ofgem identifies fraudulent consent it may reject the application and refer the case to the police.

From voucher issue to installation: the deadlines

After its eligibility checks, Ofgem emails the installer a voucher for the grant amount. The installer then has three months from the voucher issue date to complete and commission the installation, or six months for a ground source heat pump. If the work is not finished within that window, the voucher expires.

An expired voucher does not end the claim. The installer can submit a fresh application, and the property owner confirms consent again.

A separate rule covers systems that are installed first. A system must not have been commissioned more than 120 days before the voucher application is properly made. This is what lets a grant cover an installation that is already running: the application can follow commissioning by up to 120 days rather than always preceding it.

Some secondary guides still quote a 12-month voucher validity. The rule in Ofgem’s current guidance is the three-month and six-month window described above.

How the grant reaches the homeowner

The grant is never paid to the homeowner as cash. The installer shows it as an upfront discount on both the quote and the invoice, so the price the homeowner pays is already reduced by the grant value. The installer has to pass on the full grant value and must not request or accept payment of it. An installer that fails to do this risks having the voucher rejected or revoked.

Heat pump and biomass boiler installations also carry 0% VAT, in force from 1 April 2022 to 31 March 2027, which lowers the installed price separately from the grant.

Redemption and payment to the installer

The installer claims the money back after the work is done, not before. Once the new system is commissioned and its MCS installation certificate has been generated, the installer applies to Ofgem to redeem the voucher. Ofgem runs final eligibility checks, including a review of the MCS installation certificate. Once the redemption is approved, payment is scheduled for the next payment day, and payments run weekly.

Installer certification, consumer codes and the pass-on rule

Several conditions attach to the installer and the installation:

• MCS certification for the relevant technology.
• Membership of an approved consumer code, such as the Renewable Energy Consumer Code (RECC) or the HIES (Home Insulation and Energy Systems) Consumer Code.
• Passing on the full grant value as an upfront discount.
• For air-to-water and ground source heat pumps, a minimum SCOP of 2.8. SCOP measures the heat delivered across a season for each unit of electricity used.
• A system sized to meet the property’s full space heating and hot water demand, with any supplementary heating not fossil-fuelled.
• Products drawn from the BUS product eligibility list, a subset of the MCS product list.

The consumer code membership gives the homeowner protections that sit alongside the grant. HIES, for example, provides insurance for deposits and stage payments and access to independent dispute resolution, and RECC’s code is designed to work with the MCS installer standards. Both are approved by the Chartered Trading Standards Institute.

Which properties and heating systems qualify

Eligibility attaches to the property and its existing heating as well as to the technology:

• The applicant has to own the property. Businesses, second homes, rentals and self-builds are included.
• The installation has to replace an existing fossil fuel or electric heating system, such as oil, gas, electric or LPG.
• New builds do not qualify while the developer is building. A finished new build that someone has moved into with a fossil fuel boiler can qualify.
• Self-builds qualify with proof, except for biomass.
• Social housing does not qualify.
• A property that has already had government funding for the same heat pump or biomass boiler, including through the Energy Company Obligation (ECO), cannot claim again.

Where the property has a valid Energy Performance Certificate (EPC), its certificate number has to be given with the application. Where there is no valid EPC, Ofgem may accept alternative evidence.

Ofgem’s checks, including after payment

Ofgem can carry out compliance checks at any point in the process, including after it has paid the grant. These take a few forms: desk audits that review the submitted documents, site audits where Ofgem visits the property to verify the installation and separate MCS checks where MCS may contact the property owner directly. Ineligibility or non-compliance found at any stage can lead to the application being rejected, the voucher revoked or further action. The detailed audit rules sit in Ofgem’s guidance for property owners and for installers.

Why a voucher does not always become an installation

A voucher is not a guarantee that the installation happens. Ofgem’s update to 30 June 2026 recorded 135,500 voucher applications and 87,266 redeemed vouchers. Its published figure of 93,323 vouchers issued excludes vouchers later expired, revoked or withdrawn, so these totals are a live administrative snapshot rather than a simple conversion rate. Some applications are still being assessed or remain within their installation window, while other vouchers expire before the work is finished and require a fresh application.

Related entries

• Boiler Upgrade Scheme technology categories
• Air-to-water heat pumps
• Ground source heat pumps
• MCS
• SCOP performance estimate
• Zero-rated VAT on energy saving materials
• Energy Performance Certificate (EPC)