Boiler Upgrade Scheme adds air-to-air heat pumps

New rules for heat pump grants arrive on 28 April 2026. The government has corrected and reissued the law so it matches what was actually signed: Statutory Instrument 2026/390 replaces 2026/368 on the official legislation website. The changes apply in England and Wales, were made on 19 March and laid before Parliament on 1 April.

Let’s get our bearings. The Boiler Upgrade Scheme (BUS) funds low‑carbon heating in homes and small non‑domestic buildings. It supports heat pumps and, in some cases, biomass boilers, but not if you would be swapping out an existing renewable system. According to the Explanatory Note, the scheme’s life is also extended to 2030, giving households and installers a longer planning window.

The headline update is that air‑to‑air heat pumps now qualify. Picture a reversible air conditioner that moves heat from the outside air and blows warm air indoors; that’s an air‑to‑air system. These are eligible for grants in homes, but not in non‑residential buildings. New grant categories for air‑to‑air appear in the updated scheme tables, so installers can quote against them once the rules start.

The regulations also tidy up definitions. An air‑to‑water heat pump is now named explicitly, describing a unit that heats liquid for radiators or underfloor circuits, while a ground‑source heat pump warms liquid using energy from the ground for space heating. A ‘building’ is clarified as a permanent roofed structure, which helps cut disputes about what counts.

There are clear size and performance limits. Most single systems must be no larger than 45 kilowatt thermal. Shared ground‑loop systems can go up to 300 kWth, and where more than one heat pump is installed, the combined cap is 70 kWth. Air‑to‑water and ground‑source models must reach a seasonal coefficient of performance of at least 2.8. In practice, that means a reasonably efficient heat pump designed and sized for your property, not a token add‑on.

Whole‑home coverage is the expectation. Your heat pump must be able to meet your full space‑heating demand on its own, even if you keep a supplementary appliance. A supplementary appliance is fine if it is not fuelled by fossil fuel-think electric heaters or another low‑carbon unit. The new installation should also replace the heat‑generating parts of your original system, apart from any agreed supplementary appliance.

Hot water is handled more clearly. Where water heating is present, the overall set‑up must meet both your heating and hot‑water needs, either through the heat pump or in combination with permitted supplementary appliances. That wording leaves space for air‑to‑air systems, which heat rooms but do not make hot water directly.

Paperwork gets simpler on Energy Performance Certificates (EPCs). A valid EPC is no longer a pass/fail requirement for your home to be an ‘eligible property’. If you have a current EPC, you’ll provide its reference; if it’s expired, you may be asked for that number instead, plus any extra details needed to verify what’s in your home. A small drafting fix also removes EPC wording from the ‘related property’ definition to keep forms cleaner.

Installer rules are more straightforward. An ‘installer’ now means someone certified under the Microgeneration Certification Scheme (MCS). The Secretary of State can approve future versions of MCS, but the idea of an ‘equivalent’ scheme has been dropped. For you, this is a simple check before you sign: choose an MCS‑certified business and keep their certificate details with your quote.

Money flow is tightened to protect applicants. Installers must deduct the value of the BUS voucher from the price they quote you, right at the start. They cannot later ask you to pay that deducted amount unless your application is refused or a voucher is revoked. You should see the grant reflected on the invoice, so you are not fronting cash for the government support.

Location criteria use current data. ‘Urban area’ now follows the Office for National Statistics 2021 rural‑urban classification, aligning BUS with the geography used across government datasets. That helps ensure any location‑based elements are applied consistently.

Timings and continuity are clear. These amendments were made on 19 March 2026, laid on 1 April, and take effect on 28 April 2026. If your grant application was properly made before the start date, the pre‑amendment 2022 rules continue to govern your case. Internally, the regulations also refresh key dates, listing relevant financial years from 1 April 2026 through 1 April 2029, and confirm the scheme runs to 2030.

If you’re getting ready to apply, start by choosing the right technology for your home: air‑to‑air if you want warm air in specific rooms, or air‑to‑water/ground‑source if you need to heat water for radiators and taps. Speak to an MCS installer, ask them to confirm the design meets your full space‑heating load, check that the BUS voucher is shown as deducted on your quote, and keep any EPC reference-current or expired-within reach. We’ll keep explaining each step so you can make a confident, low‑carbon choice for your home.