What an Air-to-Air Heat Pump Is
An air-to-air heat pump takes heat from the outside air and delivers it straight into a room as warm air, through wall-mounted or ceiling indoor units fed by an outdoor condenser. If that sounds like air conditioning, it is — the same hardware, run in reverse. Most units heat and cool, which is why they are often sold as air conditioning in the UK.
The critical difference from a conventional heat pump is what it does not do. An air-to-air system has no water circuit, so it does not feed radiators or underfloor heating, and it does not produce hot water. Households keep a separate hot water solution — usually an immersion cylinder, an electric shower or an existing combi retained for water only.
The grant in one line: from 28 April 2026, the Boiler Upgrade Scheme pays £2,500 off the cost and installation of air-to-air heat pumps for residential properties only.
How Much the Grant Is and When It Started
The Boiler Upgrade Scheme was extended on 28 April 2026 to include air-to-air heat pumps at a flat £2,500. That sits alongside the scheme's existing rates: £7,500 for an air source or ground source heat pump, and £9,000 for oil and LPG homes off the gas grid until 31 March 2027.
The £2,500 is a fixed amount, not a percentage. It is deducted from your quote by the installer, so you never handle the money. The grant is for residential properties only — commercial premises, however small, are outside it.
| System | Boiler Upgrade Scheme grant |
|---|---|
| Air source heat pump (wet system) | £7,500 |
| Ground source heat pump | £7,500 |
| Air source or ground source, oil/LPG off-gas home | £9,000 until 31 March 2027 |
| Air-to-air heat pump | £2,500 from 28 April 2026 |
Note that air-to-air is not eligible for the £9,000 off-gas uplift. If your home runs on oil or LPG with no gas connection, a wet air source system attracts £9,000 against an air-to-air's £2,500, which is usually decisive.
What It Typically Costs
Air-to-air is the cheapest heat pump route to install because there is no wet system to design, no cylinder and far less pipework. Typical installed prices for a multi-split serving two to four rooms run £3,000 to £7,000, depending on the number of indoor units, the run lengths and how difficult the outdoor unit is to site.
- Single room (one indoor unit): typically £1,500-£3,000
- Two to three rooms: typically £3,000-£5,000
- Four rooms or more: typically £5,000-£7,000
With £2,500 deducted, a two or three room installation can land somewhere around £500 to £2,500 out of pocket. These are typical ranges rather than quotes — get at least two written prices before committing.
Who It Suits
Air-to-air is a genuinely good answer for some homes and a poor one for others. It tends to suit:
- Flats and small homes where there is no room for a hot water cylinder and no practical route for new radiator pipework.
- Homes on electric storage heaters. This is the strongest case. Old storage heaters convert electricity to heat at roughly one-to-one; a heat pump delivers around three units of heat per unit of electricity, so running costs can fall substantially.
- Properties where a wet system is impractical — solid floors, listed buildings, or a layout where lifting floors is unrealistic.
- Homes that also want cooling. Most air-to-air units cool as well as heat, which no wet heat pump system offers as standard.
- Part-heated homes, such as a converted loft, annexe or garden room heated independently of the main system.
It suits you less well if you have a working wet central heating system and a hot water cylinder already, because you would be abandoning distribution you have already paid for and still needing a separate answer for hot water.
Who Qualifies
Eligibility rules mirror the rest of the Boiler Upgrade Scheme:
- The property is residential and in England or Wales.
- You own it. Owner-occupiers and private landlords both qualify. There is no means test — income and benefits are irrelevant.
- You have a valid EPC issued within the last ten years. The old rule requiring no outstanding loft or cavity wall insulation recommendations was removed on 8 May 2024.
- The installer is MCS-certified for the technology being fitted, and is a member of a consumer code — RECC or HIES.
- One grant per property. You cannot claim £2,500 for air-to-air and £7,500 for a wet system on the same property.
Air-to-Air vs Air-to-Water: the Honest Comparison
| Air-to-air | Air-to-water (standard ASHP) | |
|---|---|---|
| Grant | £2,500 | £7,500 (£9,000 oil/LPG off-gas) |
| Typical install cost | £3,000-£7,000 | £10,000-£15,000 |
| Heats rooms | Yes, via indoor units | Yes, via radiators or underfloor |
| Hot water | No — separate solution needed | Yes, via cylinder |
| Cooling | Usually yes | Rarely |
| Disruption | Low — no wet works | Higher — pipework, radiators, cylinder |
| Indoor appearance | Wall or ceiling units in each room | Radiators, plus a cylinder cupboard |
| Best for | Flats, storage heater homes, no cylinder space | Homes with existing wet heating, off-gas homes |
Both are heat pumps and both are far more efficient than direct electric heating. The choice comes down to whether you have — or want — a water-based distribution system and where your hot water comes from.
How to Apply
The process is the same as the rest of the scheme, and you do not apply yourself.
- Find an MCS-certified installer for air-to-air heat pumps who belongs to RECC or HIES. Not every air conditioning firm holds the right MCS certification, so check before the survey.
- Get a survey and a written quote showing the total price, the £2,500 deducted and your balance.
- Decide your hot water plan. If your current boiler is being removed, agree in writing what provides hot water afterwards.
- The installer applies for the voucher. Ofgem will contact you to confirm you consent.
- The install is commissioned within 120 days of the voucher being issued.
- You pay the balance to the installer.
If you are weighing this against other options, our guides to heat pump grants and the forthcoming heat battery grant cover the alternatives, and the heat pump cost guide sets out wet system pricing in more detail.