HEAT PUMPS GUIDE
Air to Air Heat Pump 2026: Is It Right for Your Home?
An air to air heat pump heats and cools your home by moving warmth from outdoor air into indoor units, but it won't heat your water.
An air to air heat pump heats and cools your home by moving warmth from outdoor air into indoor units, but it won't heat your water.
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An air to air heat pump heats and cools your home by moving warmth from outdoor air into indoor units, but it won't heat your water. Systems cost £1,500 to £3,500 per room, and they are not eligible for the Boiler Upgrade Scheme. They're best for homes without wet radiator systems or where ducted heating makes more sense than retrofitting pipework.
You've probably seen the wall-mounted units in hotel rooms or offices. Those split-system units that blow warm or cool air? That's an air to air heat pump.
The outdoor unit extracts heat from the air outside, even when it's cold, and a refrigerant cycle concentrates that heat before passing it to one or more indoor units. In summer, the process reverses to provide cooling. The technology is identical to an air conditioning system, just marketed differently depending on whether you're buying it for heating or cooling. In practice, a modern air to air system does both equally well, which is why they're popular across Scandinavia where winters are brutal and summers increasingly warm.
Here's the key limitation: they don't heat water. No hot taps, no showers, no filling a bath. You'll still need a separate system for domestic hot water, whether that's an immersion heater, a combi boiler, or a dedicated hot water heat pump.
For space heating alone, though, they're remarkably efficient. A typical unit delivers 3 to 4 kW of heat for every 1 kW of electricity consumed, giving you a coefficient of performance (COP) of 3 to 4. That's three to four times more efficient than a direct electric heater.
This is the question we see most often. And honestly, the answer depends on what you're replacing.
An air to water heat pump heats water that flows through radiators or underfloor heating, and it also heats your domestic hot water. It's a full replacement for a gas boiler. It connects to your existing wet central heating system (though you might need larger radiators). The Boiler Upgrade Scheme gives you £7,500 off the cost, and a typical installation runs £8,000 to £14,000 before the grant.
An air to air heat pump blows warm air directly into rooms. No radiators, no pipework, no hot water. Air-to-air systems are not eligible for the BUS grant, and the total cost is lower than air to water.
So when does air to air make sense?
If you don't have a wet radiator system. Some homes, particularly older properties with storage heaters or electric panel heaters, have no central heating pipework at all. Installing a full wet system from scratch costs thousands before you even think about the heat pump. Air to air sidesteps that entirely.
If you want room-by-room control. Each indoor unit operates independently. You heat only the rooms you're using. For someone who works from home in one room all day, this can be more efficient than heating an entire house.
If you want cooling too. Air to water systems don't cool your home. Air to air does. With UK summers getting hotter, and the Met Office recording 40°C for the first time in 2022, this matters more than it used to.
If budget is tight. A single-room system can cost under £2,000 installed. A multi-split system covering three or four rooms might hit £6,000 to £10,000. Both are significantly cheaper than a full air to water installation.
But if you want a single system that handles heating and hot water and replaces your boiler entirely, air to water is the better choice. Full stop.
£1,500 to £3,500 per room. That's the realistic range for a wall-mounted split unit including installation.
A single-split system (one outdoor unit, one indoor unit) for a living room or home office typically lands between £1,500 and £2,500. Multi-split systems, where one outdoor unit feeds two to five indoor units, cost more but offer better value per room.
Here's what we typically see:
| System type | Typical cost (installed) | Rooms covered |
|---|---|---|
| Single-split | £1,500–£2,500 | 1 |
| Dual-split | £3,000–£5,000 | 2 |
| Multi-split (3-4 rooms) | £5,000–£8,000 | 3–4 |
| Ducted whole-house system | £8,000–£14,000 | Whole property |
Ducted systems are a different beast. They use concealed ductwork in ceilings or floors to distribute air throughout the house, and they're typically only practical in new builds or major renovations where you can route the ducts during construction.
Running costs depend heavily on your electricity tariff and how well-insulated your home is. A well-insulated three-bedroom house might spend £500 to £800 per year on electricity for a multi-split system. Poorly insulated? Double that. Which brings us to an important point: insulation should come first. Always.
Daikin, Mitsubishi Electric, and Panasonic dominate the UK market. Samsung and LG are increasingly competitive, particularly at the budget end. Fujitsu is strong in the commercial sector but also makes residential units. If you're comparing brands, Mitsubishi's Zen range and Daikin's Stylish series are the ones we hear installers recommend most for living spaces where appearance matters.
No. Air-to-air heat pumps are not eligible for the Boiler Upgrade Scheme (BUS). The BUS covers air to water heat pumps (£7,500 grant) because they replace a gas or oil boiler and provide both space heating and domestic hot water. Air-to-air systems provide space heating only and are excluded from the scheme.
Right, what about ECO4? If your household receives qualifying benefits like Universal Credit, Pension Credit, or Child Tax Credit, ECO4 can fund energy efficiency measures at no cost to you. However, ECO4 typically funds insulation and boiler replacements rather than air to air systems. It's not impossible, but it's rare. If you're on benefits and interested in a heat pump, check what's available through Warm Homes: Local Grant first, as local authorities sometimes have more flexibility.
Almost certainly yes, which is part of the appeal.
The outdoor unit needs wall space or ground space outside, with adequate airflow around it. It's smaller and lighter than an air to water unit's outdoor compressor. A typical residential unit measures about 800mm wide by 550mm tall. You need roughly 200mm clearance on each side.
Indoor units mount high on interior walls. They need a power supply and a conduit running through the wall to the outdoor unit (two copper pipes, a drain hose, and a cable). The hole through the wall is about 70mm diameter. Not nothing, but not major building work either.
Planning permission? Usually not needed. Air source heat pumps benefit from permitted development rights in England, provided you meet noise limits and the outdoor unit doesn't face a highway. Scotland, Wales, and Northern Ireland have slightly different rules, so check with your local authority if you're outside England.
The homes where air to air works best:
And honestly, if your home already has a functioning gas boiler and wet radiator system, air to air probably isn't your best move. You'd be adding a parallel system rather than replacing what you have. In that scenario, an air to water heat pump makes more sense when your boiler eventually dies.
A brief aside: air to air heat pumps are incredibly popular in Japan, where something like 90% of homes have them. The UK is decades behind on this, partly because we've been so reliant on gas. But with electricity prices likely to fall relative to gas as the grid decarbonises, that gap will close. Anyway.
MCS certification. That's the non-negotiable.
MCS certification is still worthwhile, it demonstrates installer competence and is often required by manufacturer warranties. The MCS installer database lets you search by postcode and technology type. As of early 2025, there were around 3,500 MCS-certified heat pump installers in the UK, though not all of them install air to air systems specifically.
Some installers come from the air conditioning trade rather than the plumbing and heating trade. This is actually fine for air to air, since there's no wet system involved. Companies like Mitsubishi Electric and Daikin maintain their own approved installer networks (Mitsubishi's is called "Accredited Installer" and Daikin's is "D1+") which can be useful starting points.
Get three quotes. Minimum.
We say this on every guide because it genuinely matters. Pricing varies enormously. One installer might quote £2,200 for a single-split system that another quotes £3,500 for. The difference is often labour rates and margin rather than equipment cost.
When comparing quotes, check:
If you're also thinking about improving your home's insulation before installing a heat pump, that's usually the smarter order. Better insulation means a smaller, cheaper heat pump can do the job. Our guide to improving your EPC rating covers the cheapest upgrades first.
And if you're weighing up whether a heat pump of any type is worth the investment, we've broken down the honest numbers here.
Common questions