How long does an installer have to redeem the Boiler Upgrade Scheme voucher?

The scheme is installer-led. An MCS certified installer applies for the grant on the property owner's behalf, discounts the grant from the invoice, applies to Ofgem for a voucher, and redeems that voucher after the installation has been commissioned². Ofgem then pays the installer, and the household's benefit arrives as a reduced upfront cost rather than a payment³. The household's practical job is to know the dates and to give consent promptly when Ofgem asks.

What the voucher is, and who redeems it

A Boiler Upgrade Scheme voucher is Ofgem's confirmation that a specific property and a specific installation have met the eligibility requirements, and that a stated grant value is reserved for that job. It is issued to the installer, not to the householder. The scheme is installer-led: installers who are MCS certified can apply for and redeem Boiler Upgrade Scheme vouchers on behalf of property owners⁷. The application is installer-led, with the installer applying for the grant on the property owner's behalf².

That structure explains why the deadlines sit with the installer. The installer submits the voucher application, Ofgem issues the voucher, the installer submits a voucher redemption application after commissioning, and the installer receives the grant payment⁴. Ofgem pays the installer when the installer redeems the voucher, with the owner benefiting through the reduced upfront cost³.

The household still has a role. Ofgem contacts the property owner, and consent must be given within 14 days of that contact³. Where a voucher is revoked, Ofgem notifies the installer within 14 days of the decision⁸. Installers can request a review of a decision, and that request must be received within 28 days of the date of the notice of the decision being reviewed⁹.

For a household weighing the scheme against supplier-funded work, the Boiler Upgrade Scheme and ECO4 routes are separate, and the application process is where the dates are set.

The two-stage application: voucher issue and redemption

The grant application is a two-stage process⁴. Stage one is the voucher application: the installer submits it, and Ofgem issues a voucher if the property and technology qualify. Stage two is redemption. Following commissioning of an installation the installer can submit a voucher redemption application (stage 2a), and once Ofgem has established that the remaining eligibility requirements have been met, the grant payment is made (stage 2b)⁵.

Redemption is not a formality, but it is quick once the paperwork is in order. Across Scheme Year 3, Ofgem processed and paid 96% of applications for voucher redemptions within 10 working days of the request⁶. Payments run on a weekly schedule, with a maximum gap of five working days between approving a redemption application and sending payment for most applications; payments move to the following working day after a public holiday¹⁰.

The volume gives a sense of scale. In the quarter from August 2025 to October 2025 there were 8,233 voucher redemption applications⁴. Total voucher applications reached 102,735⁴. Between May 2022 and March 2026 the scheme paid just over 80,000 grants worth £560 million¹¹.

A voucher that has been issued keeps its value. Any vouchers that have been issued will receive the grant value stated on the voucher when they are submitted for redemption, and remain redeemable before and after 23 October 2023¹⁰. That matters where grant levels change mid-project: the voucher, not the current published rate, is the figure that gets paid.

Voucher validity: 3 months for air source, 6 months for ground source

The validity period depends on the technology, and the reason is practical. Air source heat pump, air-to-air heat pump and biomass boiler vouchers run for 3 months¹. Ground source heat pump vouchers run for 6 months¹. Ofgem's own summary of the position is blunt: vouchers for ground source heat pumps are valid for 6 months¹. The quarterly reporting states the same split, that vouchers for air source heat pumps and biomass boilers are valid for 3 months⁴.

Ground source work takes longer because it involves ground loops or boreholes, excavation and, often, planning or access arrangements. The extra three months reflects that, not a difference in the grant itself.

Validity periods are fixed. Ofgem states that it cannot extend validity periods under any circumstances⁹. A household that has not had the installation commissioned before the voucher lapses has no route to an extension, and the grant is lost.

The 120-day commissioning application deadline

The 120-day rule is the second clock, and it works in both directions. The application must be properly made within 120 days of the commissioning date¹. Read the other way, the heating system must be commissioned no more than 120 days prior to the voucher application being properly made⁷. Independent guidance puts it plainly: heating systems commissioned up to 120 days before the application is submitted are entitled to support under the scheme¹².

This is what allows a retrospective application. Installers may apply for a Boiler Upgrade Scheme voucher after the installation has been commissioned, provided the application is properly made within 120 days of commissioning¹³. A household that had a heat pump fitted without a grant application in place is not automatically excluded, provided the dates fall inside the window.

There is a floor as well as a ceiling. Heating systems must be commissioned on or after 1 April 2022 to be eligible¹⁰. Vouchers were issued from 23 May 2022 on eligible technologies installed from 1 April 2022¹⁴.

Ofgem has tightened the language around this rule over time. A 2024 update to the property owner guidance promised greater clarity to the 120-day commissioning rule¹⁵. The practical effect for a household is that the commissioning date on the certificate is the anchor for everything: it sets the outer limit for the application, and it is the date an installer will be asked to evidence.

Scheme dates: when applications open and close

The scheme opened for applications on 23 May 2022¹⁶. It has run in scheme years since, with Scheme Year 2 covering 1 April 2023 to 31 March 2024¹⁷. It remains open for grants towards heat pump installations across England and Wales¹⁸.

The closing date is published. The scheme is scheduled to close at 11:59pm (Midnight) on 30 December 2029⁶. That is the deadline for new applications, not for redemptions of vouchers already issued.

The grant rate changed during the scheme's life. The higher grant only applies to new applications submitted from 21 July 2026¹⁹. Applications submitted before that date sit on the earlier rate, and the voucher issued at the time records the value that will be paid¹⁰.

What happens if the voucher expires or the budget runs out

Vouchers are issued on a first come, first served basis, to applicants who meet the eligibility requirements, until the budget cap for the financial year is reached²⁰. That is the mechanism behind the scheme's occasional pauses: the constraint is the annual budget, not the number of qualifying homes.

Expiry is common enough to be measured. In Scheme Year 3, a further 3,638 vouchers expired before they were redeemed²¹. In Scheme Year 2, a further 2,128 expired before they were redeemed¹⁷. Earlier reporting found around 10% of air source heat pump and biomass boiler vouchers expiring for the November 2023 to January 2024 cohort, in line with previous quarters²².

The pattern is consistent: a meaningful minority of vouchers are never redeemed, usually because the installation slipped past the validity window or the household changed its plans. Because validity cannot be extended⁹, an expired voucher means a fresh application, a fresh eligibility check and whatever grant rate applies at that point.

Eligibility conditions that sit alongside the deadline

The deadline is only one of the conditions, and a voucher that is redeemed still has to satisfy the rest. Properties are no longer required to have a valid Energy Performance Certificate to apply for the Boiler Upgrade Scheme from 28 April 2026, but where an EPC exists, the certificate number must be provided⁹. The government had already set out its intention to amend eligibility criteria to relax the EPC requirement from 2026/27 onwards, adopting a hybrid model²³.

The grant limit is one per property⁵. A second heat pump at the same address does not attract a second voucher.

Funding cannot be stacked. Funding from the Boiler Upgrade Scheme and ECO cannot be blended for the same measure or be included within an ECO4 project²⁴. ECO4 funding must not be blended with funding from other government schemes or grants, including the Warm Home Discount, the Boiler Upgrade Scheme, the Social Housing Decarbonisation Fund and the Home Upgrade Grant²⁵. A household choosing between the two routes is choosing, not combining. The ECO4 and other grants page sets out how that separation works in practice.

Where the deadline leaves the household

The scheme does real work for energy independence: it moves a home off a fossil fuel boiler and onto a heat pump, cutting the gas connection's share of the household's heating. What it does not do is remove dependence. The heat pump runs on electricity from the grid, bought from a supplier, and the grant itself depends on an installer staying within Ofgem's windows and on an annual budget that can be exhausted. The household's exposure is to the installer's administrative timing as much as to the technology.

The dates are therefore worth tracking directly. The voucher validity period, 3 months or 6 months depending on technology¹, and the 120-day commissioning window¹ are the two figures that decide whether a grant is paid. Both are fixed, neither can be extended⁹, and both are measured from dates the installer records. A household that knows its commissioning date and its voucher issue date can see the deadline coming.

Where a query arises, complaints about Ofgem's administration of the scheme can be sent to feedback@ofgem.gov.uk⁷. The wider picture of how grants fit into a home's energy position is set out in grants and energy independence.