Why Boiler Upgrade Scheme installers end up funding the grant
The government’s final evaluation of the Boiler Upgrade Scheme shows the grant is doing its job for households. It also shows that many of the firms fitting the systems are carrying the cost of waiting to be paid.
What the final evaluation found
The Department for Energy Security and Net Zero published its final evaluation of the Boiler Upgrade Scheme on 24 September 2026. It covers the scheme’s original phase, from 2022 to 2025, in England and Wales.
The headline finding is that the grant changed decisions. The evaluation estimates that 74% of BUS-funded installations were additional: 36,508 of 49,136 systems that would not otherwise have been fitted.
The finding that matters most for installers sits further down. The delay between completing an installation and receiving the grant payment caused cash flow problems for 29% of installer companies. The report treats that delay as built into the way the scheme is designed, not as an administrative hiccup.
Why the payment gap is an operating issue
On a BUS job, a large share of the price is paid by the grant, and that money arrives after the work is finished. Until it lands, the business has already paid for the equipment, the labour and the van. In practice, it is lending the grant to the scheme.
One job at a time, that is manageable. The pressure builds with volume. More BUS work means more money owed at any one moment, so a firm can be busier and more profitable on paper while having less cash in the bank. The pattern is familiar from any business where profit and cash drift apart.
The scheme itself is not going away. Government funding for BUS now runs to 2030, so the firms that plan around the gap will be better placed to take on the work as it grows.
What to check in your own business
- How long does BUS payment take? The average number of days from completion to grant payment, measured rather than guessed.
- How much is owed right now? The total value of grants due on finished jobs, reviewed alongside the bank balance.
- Does the plan allow for it? Whether quoting, scheduling and the cash forecast account for money that arrives weeks after the work.
The same discipline applies to every stage of getting from a won job to cash in the bank, and to protecting cash flow and working capital more widely.
Sources
- Department for Energy Security and Net Zero: Evaluation of the Boiler Upgrade Scheme, 2026 (final report, published 24 September 2026)
- Department for Energy Security and Net Zero: Boiler Upgrade Scheme 2026 to 2030: Summary Business Case