Boiler Upgrade Scheme Annual Report April 2025 to March 2026

The Boiler Upgrade Scheme (BUS) launched on 23 May 2022 to support the decarbonisation of heat in buildings. It provides upfront capital grants towards the cost of installing approved heat pumps and, in limited circumstances, biomass boilers in homes and small non-domestic buildings in England and Wales.  

Changing the way we heat our homes and businesses, by replacing fossil fuel and direct electric heating systems with lower carbon alternatives, is essential to decarbonise our energy system and the BUS is playing an important role in supporting this. 

Voucher summary 

• During Scheme Year 4, we received 45,880 BUS applications, an increase of 19% on the applications received during Scheme Year 3. 
• After completion of our pre-installation eligibility checks we issued a total of 39,435 vouchers during Scheme Year 4 worth over £295.5 million. 

Analysis of grants paid 

• During Scheme Year 4 we paid grants worth £233.1 million, supporting the installation of 31,104 low-carbon heating systems. This brings the total value of grants paid since the start of the scheme to £560.3 million, supporting 80,098 low-carbon heating systems. 
• Since the start of the scheme, 97.6% of grants paid were for air source heat pumps and around 76.3% were for the replacement of fossil fuelled heating systems, like gas boilers. 
• 1,789 active installers are registered under the BUS and the top 10 installers (by application volumes) are responsible for over 36.5% of all grant applications received in Scheme Year 4. 

Monitoring compliance 

• 1,042 applications were audited in Scheme Year 4 with an initial compliance rate of 93.1%. Note that following an audit, where possible, we instruct the applicant to take corrective action. As such some of those initially assessed as being non-compliant may subsequently be brought into compliance. 
• We also closed 876 compliance investigations in Scheme Year 4, of which 367 (41.9%) were found to be non-compliant. Through our compliance action and other administration activities in Scheme Year 4, we prevented £3.6 million of public funds being paid incorrectly and identified a further £1.2 million for recovery.  

 For those wishing to look at the data used in the report in more detail, a spreadsheet with this information is published below.