Is there a grant for air to air heat pumps? The Boiler Upgrade Scheme in 2026

What changed

For years, the Boiler Upgrade Scheme, or BUS, only paid towards air to water and ground source heat pumps and biomass boilers. Air to air systems, the reversible units that look like air conditioning, were left out. That has changed.

The Energy Saving Trust reports that the government announced the expansion in November 2025, and the gov.uk scheme page, updated in October 2026, now lists:

Technology	BUS grant
Air source (air to water) heat pump	£7,500
Ground source heat pump	£7,500
Biomass boiler	£5,000
Air to air heat pump	£2,500

You can get one grant per property. Hybrid systems, such as a gas boiler working with a heat pump, are not eligible.

Who qualifies

Ofgem, which runs the scheme, sets the rules. In short:

• the property must be in England or Wales
• for air to air, it must be residential: non residential buildings are excluded
• the installer must be certified by the Microgeneration Certification Scheme (MCS)
• the new system must replace an existing fossil fuel or electric heating system
• it must not replace an existing low carbon system
• a heat pump must be sized to meet the property’s full space heating needs
• new builds are excluded, apart from some self builds
• social housing, including shared ownership, is excluded
• the property must not already have had government or ECO funding for the same system

The grant is installer led. Your installer applies, Ofgem contacts you to confirm consent, and the grant should appear as a discount on your quote. The installer then has three months from approval to finish the job.

The catch: MCS certification for air to air

This is the part that matters for anyone planning an install now. According to the Energy Saving Trust, updated on 20 October 2026, there are currently no MCS certified installers for air to air heat pumps, and MCS expects certification to be available before the end of 2026. Until installers and products are certified, nobody can make a grant funded air to air installation.

What that means in practice:

• if you want the £2,500, you will need to wait until MCS certified air to air installers appear on the MCS find an installer tool
• if you install now with a non MCS installer, you will not be able to claim the grant later for that system
• if you need cooling before next summer and are happy to pay in full, you can go ahead now

The Energy Saving Trust also notes that the scheme may not include every type of air to air system, though it expects the most common ones to be covered.

Why this matters in London

Air to air heat pumps suit the kind of homes London has most of. Over half of London households live in flats, and some London flats, particularly in purpose built blocks, are heated by electric storage or panel heaters. They have no radiators to connect an air to water heat pump to and no room for a large outdoor unit or cylinder upgrade. A reversible air to air system can replace electric heaters with something far more efficient and give cooling in summer as well.

That said, flats bring their own steps before any grant: freeholder consent, and usually planning permission, because permitted development only allows one heat pump on a whole block. Our Westminster area page explains how that works in conservation areas and mansion blocks.

Heating first, cooling second

To qualify, the system must be designed to heat your home through winter. That is a different design from a cooling first air conditioner:

• it is sized for the coldest days, using a heat loss calculation for each room
• it has to replace your existing heating, not sit alongside it
• you need a separate plan for hot water, because most air to air systems do not heat water

A system designed for heating also fits the planning rules better: in England, a heat pump can be permitted development under Class G only if it is not used solely for cooling.

VAT

Ofgem’s page says there is 0% VAT on installing energy saving materials, including heat pumps, from 1 April 2022 to 31 March 2027. Ask your installer to confirm how it applies to the system you are buying. Cooling only air conditioning is not a heat pump installation in this sense.

What to do now

1. Decide whether heating is a main goal. If you only want summer cooling, the grant is not for you.
2. Get a survey and a heat loss based design so you know what a qualifying system would look like.
3. Check your lease and talk to the freeholder if you are in a flat.
4. Watch the MCS installer listings for air to air certification.
5. Compare the cost of waiting with the cost of another hot summer.

Our air to air heat pump page explains how these systems work, and our guide to air to air vs air to water helps you choose between them.