Air conditioning UK.
Costs, running costs, and honest advice for 2026.
Everything you need to know before putting air conditioning in your home. What a split system costs to install, what it costs per hour to run, whether you need planning permission, and why most modern units heat your home in winter too.
Home air conditioning in the UK usually means a wall-mounted split system. A single-room split system typically costs £1,500 to £3,000 fully installed, and runs at roughly 18p to 30p per hour at current electricity rates. Most modern units are air-to-air heat pumps, so they heat efficiently in winter as well as cool in summer. Planning permission is not normally needed, and installation usually takes a day. This guide gives you the honest picture rather than a sales pitch.
What is a split system and how does it work?
A split system is the standard way to air condition a UK home. It has two parts: a quiet indoor unit mounted high on the wall of the room, and an outdoor unit that sits outside on a wall or the ground, connected by slim refrigerant pipes. It cools the same way your fridge does, by moving heat from one place to another.
Indoor unit absorbs heat from the room
Warm room air is drawn across a refrigerant-filled coil in the indoor unit. The refrigerant absorbs the heat and the unit blows the cooled air back into the room. Filters catch dust and pollen on the way through, which is why air conditioning also helps many hay fever sufferers in summer.
Heat is pumped outside
The refrigerant carries the absorbed heat through the pipework to the outdoor unit, where it is released into the outside air. A compressor drives the cycle, and on modern inverter units it adjusts its speed continuously to match the room rather than switching on and off at full power.
In winter the cycle runs in reverse
Most modern split systems are air-to-air heat pumps. Flip them to heating mode and the same cycle runs backwards, extracting heat from outside air and delivering it into the room. In mild weather they can deliver around three units of heat for every unit of electricity, far cheaper than a plug-in electric heater.
Split, multi-split or portable: which should you get?
The decision usually comes down to how many rooms you want to cool and whether you own the property. Here is how the options compare.
Single split system
One indoor unit cooling and heating one room, usually a bedroom or living room. Quiet, efficient, permanently installed, and typically fitted in a day. The right choice for most homeowners starting with air conditioning. Adding further rooms later usually means separate units or stepping up to a multi-split.
Multi-split system
One outdoor unit running two to four indoor units in different rooms. Tidier outside than multiple single splits and usually cheaper than installing them separately. Whole-house setups with more indoor units usually run past £9,500. Worth pricing both ways if you want more than two rooms covered.
What about portable units? A portable air conditioner costs £200 to £500 with no installation, which makes it the practical option for renters or very occasional use. The trade-offs are real: they are noisier, much less efficient, take up floor space, and need a hose hanging out of a window, which lets warm air leak back in. If you find yourself cooling the same room every summer, an installed split system usually works out better value within a few years.
How much does air conditioning cost to install?
Installed cost depends on the number of rooms, the size of unit each room needs, how far the indoor and outdoor units are apart, and how much pipework and electrical work is involved. Here are realistic fully-installed prices.
| Setup | Covers | Installed cost | Best for |
|---|---|---|---|
| Single split | 1 room | £1,500 to £3,000 | Bedrooms, living rooms, home offices |
| Multi-split | 2 to 4 rooms | £3,000 to £7,500 | Covering the main rooms of a house |
| Whole house | 5+ rooms | £9,500+ | Larger homes, full coverage |
| Portable unit | 1 room at a time | £200 to £500 | Renters, occasional use |
Installation and servicing should be carried out by an F-Gas certified engineer, which is a legal requirement for working with the refrigerant. Always compare at least two quotes before committing. If you want a price without a sales visit, you can start an online air conditioning quote with Heatable in a few minutes.
Is air conditioning expensive to run in the UK?
Less than most people assume. A modern 3.5kW split system, the size that suits a typical double bedroom or average living room, draws roughly 0.7 to 1.2kW of electricity while running. At current electricity rates that works out at roughly 18p to 30p per hour.
In practice you rarely run it flat out all day. Four hours of cooling on a hot afternoon typically costs around £1. Even a hot fortnight of heavy use usually adds £15 to £30 to an electricity bill. Inverter units keep real-world costs at the lower end because they throttle down once the room reaches temperature rather than cycling at full power.
Used for heating in winter, the same unit is one of the cheapest ways to heat a single room. Because it moves heat rather than generating it, it can deliver around three units of heat per unit of electricity in mild weather, which beats any plug-in electric heater by a wide margin.
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Get a free quoteIs air conditioning worth it in the UK?
The honest answer depends on how your home copes in summer and whether you would use the heating mode.
If your bedroom regularly sits above 25 degrees on summer nights, if you work from home in a room that overheats, or if you are already running a noisy portable unit every summer, an installed split system transforms comfort for a modest running cost. The heating mode strengthens the case further: it gives you cheap, instant heat for that room in spring and autumn without firing up the whole central heating system. UK summers are also trending hotter, and heatwave nights above 20 degrees are no longer rare.
If your home stays comfortable in all but a few days a year, a £1,500 to £3,000 install is a lot to spend for a fortnight of use, and a fan or portable unit covers the occasional hot spell. Flats can also be awkward: the outdoor unit needs somewhere to live, and leases, listed status or conservation areas can restrict installation. There is currently no government grant for air-to-air units: schemes like the Boiler Upgrade Scheme usually support air-to-water heat pump systems rather than wall-mounted air conditioning, so the full cost is yours.
Home air conditioning pros and cons
Advantages
- Proper cooling on hot days and nights, not just air movement like a fan
- Cheap efficient heating for the same room in winter, around three units of heat per unit of electricity in mild weather
- Modest running costs, roughly 18p to 30p per hour for a typical room unit
- Quiet indoor units, filtered air, and better sleep in heatwaves
- Usually installed in a day with no planning permission needed for most houses
Disadvantages
- Meaningful upfront cost for something many UK homes only need a few weeks a year
- No government grant support for air-to-air units at present
- Needs an outdoor unit, which can be awkward or restricted for flats, listed buildings and conservation areas
- Annual servicing of £80 to £150 per unit to keep efficiency and warranty
- Heating mode covers rooms, not your hot water, so it complements rather than replaces central heating
Do you need planning permission for air conditioning?
Usually not. Most home air conditioning installations in the UK fall under permitted development, so planning permission is not normally required for a typical house. The usual exceptions are flats, listed buildings and conservation areas, where rules can be stricter, and leaseholders should check their lease before committing. A good installer will confirm what applies to your property as part of the survey.
Installation for a single split system usually takes a day. The indoor unit goes high on the wall, the outdoor unit sits on an external wall bracket or the ground, and the two are connected through a small hole in the wall. Positioning the outdoor unit thoughtfully, away from bedroom windows and neighbour boundaries, keeps noise a non-issue for most installations.
Air conditioning servicing and upkeep
Annual service
A yearly service keeps efficiency up, checks refrigerant levels and keeps the manufacturer warranty valid. Booking before early summer usually beats the seasonal rush when every engineer is busy.
Service cost
Expect £80 to £150 per unit per year depending on your area and system. Multi-unit homes can usually negotiate a combined visit price covering every unit in one appointment.
DIY upkeep
Clean or vacuum the indoor unit's filters every few weeks in heavy use, and keep the outdoor unit clear of leaves and vegetation. Clean filters alone make a noticeable difference to performance.
F-Gas certified engineers
Installation and servicing must be done by an F-Gas certified engineer, which is a legal requirement for handling the refrigerant. Ask for the registration number and a commissioning sheet with your install.
Questions people ask about home air conditioning
A single split system cooling one room typically costs £1,500 to £3,000 fully installed. A multi-split covering two to four rooms typically costs £3,000 to £7,500, and whole-house systems usually run past £9,500. Portable units cost £200 to £500 to buy with no installation.
A modern 3.5kW split system draws roughly 0.7 to 1.2kW while running, which is roughly 18p to 30p per hour at current electricity rates. Four hours on a hot afternoon typically costs around £1. Inverter units keep real-world costs down by throttling back once the room reaches temperature.
Usually not. Most installations on houses fall under permitted development. Flats, listed buildings and conservation areas can be stricter, and leaseholders should check their lease. Your installer will confirm what applies to your property before work starts.
Yes. Most modern wall-mounted units are air-to-air heat pumps and run in reverse to heat the room. In mild weather they deliver around three units of heat per unit of electricity, which makes them far cheaper than plug-in electric heaters for heating individual rooms. They heat rooms rather than hot water, so they complement central heating rather than replace it.
A split system is quieter, far more efficient and more powerful. A portable unit wins on upfront cost and needs no installation, which suits renters and occasional use. If you cool the same room every summer, an installed split system usually works out better value over a few years.
Not at present. Government schemes like the Boiler Upgrade Scheme usually support air-to-water heat pump systems that replace a boiler, rather than wall-mounted air-to-air units. Air conditioning is normally a full-cost purchase, which is why comparing installer quotes matters.
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