A wall-mounted air conditioning system for one room typically costs around £1,900 to £2,600 fully installed in 2026, with the big national installers advertising from about £2,200 to £2,300. A multi-room system covering two or three rooms usually costs around £3,700 to £5,200. Running costs are lower than most people expect, often around 20p an hour for a single bedroom unit.
Below we break down where those numbers come from, what pushes a price up or down, and the rules on VAT, grants and planning that can change what you pay.
What does a typical system cost?
Most homes in the UK use a split system. That means a slim indoor unit on the wall of each room, linked by a small pipe and cable to a fan unit outside. A modern split system can heat as well as cool, so it is technically an air-to-air heat pump.
Here is what national installers and cost guides were quoting at the time of writing:
| System | Typical installed price | Notes |
|---|---|---|
| One room, wall-mounted split | £1,900 to £2,600 | National firms advertise from about £2,200 to £2,300 |
| Two to three rooms, multi-split | £3,700 to £5,200 | One outdoor unit serving several indoor units |
| Portable unit (no installation) | £300 to £650 | Cheaper, but louder and less efficient |
A few real examples. BOXT advertises air conditioning installed from £2,299. iHeat starts from £2,245, WarmZilla from £2,224, and Heatable lists single-room systems at £2,300 to £2,600 and multi-room systems at £4,195 to £5,195. Which? puts a single-room system at around £1,900 and a multi-unit system for a three-bedroom semi at around £3,700.
Prices in London and the South East tend to sit towards the upper end of these ranges, according to Checkatrade.
Why do prices vary so much?
Two homes can get very different quotes for what looks like the same job. These are the main reasons.
The size of the unit. Small bedrooms and home offices usually need a 2.5kW or 3.5kW unit. A large open-plan living room may need 5kW or more, which costs more to buy.
The brand and model. Budget and premium brands can be several hundred pounds apart. Quieter units with better efficiency ratings usually cost more upfront but less to run.
The pipe run. The further the indoor unit is from the outdoor unit, the more pipework, trunking and labour you need. Going through a solid brick wall, up a floor or across a loft adds time.
Where the outdoor unit goes. A unit on the ground is simpler than one mounted high on a wall on brackets.
Electrical work. Some homes need a new circuit or an upgrade at the consumer unit to supply the system safely.
How many rooms. Each extra room on a multi-split adds an indoor unit, more pipework and more time. A single room is usually fitted in a day. A multi-room job can take two or three days or more.
How much does air conditioning cost to run?
Air conditioning runs on electricity, so the cost depends on how much power the unit draws and what you pay per unit.
A modern 2.5kW unit typically uses around 0.6 to 0.8kWh for each hour of cooling. Modern units are efficient because they move heat rather than make it. Each unit of electricity can shift several units of heat, which is what the SEER (cooling) and SCOP (heating) ratings measure. A higher number means cheaper running.
Under the Ofgem price cap for October to December 2026, the average electricity unit rate is 26.32p per kWh for people paying by Direct Debit. The government has removed VAT from electricity bills from 1 October 2026 to 31 March 2027, so that figure is what you actually pay per unit.
That gives a rough running cost of about 16p to 21p an hour for a small bedroom unit. Checkatrade gives a wider range of 20p to 60p an hour, as bigger units and very hot days use more.
As a worked example, if you ran a 2.5kW bedroom unit for 6 hours a day across 60 hot days:
- 360 hours x 0.7kWh = 252kWh
- 252kWh x 26.32p = about £66 for the summer
Your own costs will depend on your tariff, the size of the room, how well it is insulated and the temperature you set. The price cap also changes every three months, so check your latest bill.
Do you pay VAT on air conditioning?
This is where it gets more interesting than most people realise.
Fixed air source heat pumps count as energy-saving materials for VAT, and from 1 May 2023 to 31 March 2027 their installation in homes is zero-rated. HMRC’s own guidance says that most air conditioning units are air source heat pumps, as fixed units can be reversed to provide both heating and cooling.
In practice, that means a fixed, reversible split system installed in your home by a VAT-registered installer can qualify for 0% VAT. Some points to know:
- Portable units do not qualify. The unit must be permanently fixed.
- Cooling-only units are unlikely to qualify. The system needs to work as a heat pump that can heat as well as cool.
- It applies to supply and fit together. Buying a unit on its own is not the same.
- The rate is due to rise. From 1 April 2027 the zero rate is expected to end and installations will go back to the 5% reduced rate.
Many national prices already reflect the zero rate, so check whether a quote includes VAT and at what rate.
Can you get a grant for air conditioning?
Possibly, but not for most single-room installs.
Since 28 April 2026, air-to-air heat pumps have been eligible for a £2,500 grant under the Boiler Upgrade Scheme in England and Wales. The conditions are strict, though:
- It must replace an existing fossil fuel heating system (such as gas, oil or LPG) or an electric heating system.
- The air-to-air system must meet the home’s full space heating needs.
- It must be fitted by an MCS-certified installer, in a residential property.
- You cannot use it to replace an existing heat pump or other low-carbon system.
So if you are adding a unit to a bedroom to stay cool in summer and keeping your gas boiler, the grant will not apply. If you are thinking about replacing your heating entirely, it is worth asking about.
Do you need planning permission?
Usually not, if you live in a house in England.
Since 29 May 2025, the permitted development rules for air source heat pumps have also covered air-to-air heat pumps used for cooling. Under these rules:
- A detached house can usually have up to two outdoor units without planning permission. Other houses can usually have one.
- Each outdoor unit must be no bigger than 1.5 cubic metres on a house, or 0.6 cubic metres on a block of flats.
- The installation must meet the MCS planning standard (MCS 020a), which includes a noise check.
- Units should not go on a wall above ground floor level where that wall faces a road.
Permitted development does not apply to listed buildings, and there are extra limits in conservation areas. Cooling-only systems are not covered by these rules, so they may need planning permission.
If you live in a flat, you will usually also need permission from your freeholder or management company under your lease. If in doubt, check with your local council before you go ahead.
Who is allowed to install it?
Air conditioning contains refrigerant gas, known as F gas. By law, anyone who handles F gas must hold a personal F gas qualification. Companies that install, service or repair this kind of equipment for others must also be certified by an approved body.
This is not a DIY job, and it is worth asking any installer to confirm their F gas certification before you book. Proper installation also matters for the VAT relief and for the manufacturer’s warranty.
Once fitted, a yearly service is a good idea. Checkatrade puts a one-off service at around £70 to £120 per unit, and WarmZilla at around £80 to £150.
Frequently asked questions
How much does it cost to air condition a whole house?
It depends on how many rooms you want covered. A multi-split covering two or three rooms usually costs around £3,700 to £5,200. Larger homes with more rooms will cost more. A survey is the only way to get an accurate figure.
Is it cheaper to buy a portable air conditioner?
Upfront, yes. Portable units cost around £300 to £650. But they are noisier, less efficient and need a hose out of a window. A fixed split system costs more to buy but is quieter and cheaper to run.
Can air conditioning heat my home too?
Yes. Most modern split systems are reversible air-to-air heat pumps, so they can heat a room in winter as well as cool it in summer.
How long does installation take?
A single-room system is usually fitted in one day. A multi-room system can take two to three days or more, depending on the pipe runs.
Do prices include VAT?
Check every quote. Fixed, reversible systems installed in homes can qualify for 0% VAT until 31 March 2027, after which the rate is expected to go to 5%. Cooling-only and portable units do not usually qualify.
Want a figure for your own home? Try our instant air conditioning estimate, read more about air conditioning with Solair, or check the areas we cover across Surrey, Sussex, Hampshire and London. When you are ready, request a free survey and we will send you a fixed, written price.