Boiler Upgrade Scheme

Rating: The SRO delivery confidence assessment rating for 25/26 remained at Amber. The scheme is operationally mature and performing strongly, with sustained year‑on‑year growth in deployment. Applications in 2025/26 were up 19% on 24/25, with redemptions up 21%. The BUS Evaluation evidenced a high level of property owner satisfaction at 91% and MCS outreach recorded an average 95% satisfaction rate. The implementation of scheme changes announced in the November 2025 Government Response, will improve access, stimulate demand and strengthen consumer protection, and come into force from 28 April 2026. The Full Business Case for FY 2026/27 to 2029/30 has received TAP approval, confirming funding for the remainder of the scheme timeline. While demand and delivery continue to grow, overall delivery confidence remains dependent on wider market and policy factors, including the delivery of the Warm Homes Plan; given the materiality of these dependencies, an Amber rating remains appropriate.

Schedule: The project end date in 2025/26 was extended from March 2026 to March 2030. This reflects the extension of the scheme following the Spending Review, which provided additional funding and extended delivery to March 2030.

Cost: The project’s departmentally agreed whole life cost increased due to the extension of the scheme to 2030 following the Spending Review, which increased both the duration and scale of delivery. As a result, total funding for the extension period increased with the annual budgets set out in the Warm Homes Plan in January 2026.

Source: NISTA Major Projects Annual Report 2025-26 (data)

Rating: The Infrastructure Project Authority's Delivery Confidence Assessment rating at 24/25-Q4 is AMBER. This is due to‚ The scheme being a well-established project in its fourth year of delivery that is performing strong both operationally and in terms of deployment. The £150 million budget for the 3rd year of the scheme was exceeded, allowing an increase in the deployment of heat pumps, with total deployment reaching £190 million. Moreover, the scheme has a TAP approved budget for 25/26 of £295 million which allows room for further growth to build on year three of the scheme. The operational success of the scheme, teamed with strong deployment, suggests the scheme is close to a green rating. However, external factors, such as the ongoing spending review, introduce uncertainty. Until these are resolved, the scheme will retain an Amber RAG rating.

Schedule: The project's end-date at 24/25-Q4 is scheduled to be 31/03/2026. This is primarily due to the following factors‚ The spending review outcome as this is where a decision will be made on the tenure of the scheme and the associated budgets. We expect the scheme to continue beyond the 31/03/26 date, but cannot currently confirm the exact length of this extension.

Cost: The project's departmentally agreed Whole Life Cost at 24/25-Q4 (measured in £m) is 487. This is primarily due to the following factors‚ The scheme was initially due to run for three years only with a total budget of £450 million, allocated equally at £150 million per year between 2022- 2025. Therefore the further funding was for the resourcing of the scheme across these years including funding Ofgem to administer the scheme and a small policy team at DESNZ.

Source: NISTA Annual Report 2024-25 (data)