Air Conditioning Installation UK: Costs and Quotes

Air conditioning installation in a UK home almost always means a split system: an indoor unit on the wall of the room, an outdoor unit on a wall bracket or the ground, and two insulated copper pipes plus a cable running between them. A single split for one room typically costs £1,500 to £3,000 fitted, according to Selectra’s 2026 figures. Most installs take a day or less.

We don’t fit anything ourselves. Tell us about the rooms you want cooled and we pass your request to F-Gas certified installers who cover your postcode, so you can compare their quotes.

Fitted split or portable unit?

A portable unit is cheap to buy and needs no installer, which is why so many people reach for one in a heatwave. The catch is the hose. A single-hose portable pushes hot air out of a window gap, and warm air leaks back in around it. Selectra estimates a portable costs about 26p to 35p an hour to run, against 15p to 20p for a split. Portables are also loud, because the compressor sits in the room with you.

A fitted split makes sense when:

you want a bedroom cool enough to sleep in on hot nights without the noise of a compressor beside the bed
the room gets afternoon sun through large windows or sits under a flat or loft roof
you would use it for heating in winter too, since most splits are reversible air-to-air heat pumps
you rent out or let the room and a hose through the window is a security problem

Evaporative “air coolers” are not air conditioning. They add moisture to the air and do little in humid UK heat.

How an air conditioning install works

The survey

A good installer visits or asks for photos before quoting. They measure the room, note which way it faces and how much glazing it has, and work out the cooling output you need. Too small and the unit runs flat out without keeping up. Too big and it cycles on and off, which wastes power and leaves the room clammy. They also look at where the outdoor unit can go, how far the pipes must run and whether your consumer unit has space for a new circuit.

Fitting day

The indoor unit goes on a bracket high on the wall, usually an outside wall.
A core hole is drilled through the wall for the pipes, cable and condensate drain.
The outdoor unit goes on wall brackets or a ground stand, clear of windows and boundaries.
The engineer pressure tests the pipework with nitrogen, pulls a vacuum to remove air and moisture, then releases or adds the refrigerant.
An electrician or the installer connects the power, often on its own circuit.
The system is commissioned and you are shown the controls.

Bestbuilders puts a single-room install at four to eight hours. Multi-split systems, where one outdoor unit serves several rooms, take longer because of the extra pipe runs.

The F-Gas rules your installer must follow

Split systems contain fluorinated gas refrigerant. GOV.UK says anyone who installs, services, maintains or recovers refrigerant from stationary air conditioning needs their own F-Gas qualification from City & Guilds, BESA or LCL Awards, even if they work for someone else. Ask for the engineer’s certificate number before you book.

Since 2025, new single split systems holding less than 3kg of refrigerant cannot use an F gas with a global warming potential above 750. That rules out the older high-impact gases for new home units, so be wary of a cheap quote for old stock. The quote should name the refrigerant the unit uses.

DIY kits with pre-charged quick-connect pipes are sold online. Even where fitting one is legal, you will struggle to find an engineer who will commission, service or warrant someone else’s install, and a leak means calling one out anyway.

Planning, freeholders and electrics

Houses: in England, an air-to-air heat pump that also heats can count as permitted development if it meets the heat pump conditions, including a 1.5 cubic metre size limit and one unit on a non-detached house (two on a detached house). Richmond Council’s guidance says a unit used solely for cooling is not covered. Listed buildings and conservation areas have extra limits, and Wales, Scotland and Northern Ireland have their own rules, so check with your council.
Flats: the outside wall usually belongs to the freeholder. Get written consent before you book, and check your lease.
Electrics: GOV.UK lists a new circuit from the fuse box, and installing a fixed air conditioning system, as notifiable building work in England. A registered competent person can self-certify it. Ask for the electrical installation certificate along with the commissioning paperwork.
Neighbours: outdoor units hum and blow warm air. Keep them away from a neighbour’s bedroom window.

The £2,500 grant for heat-and-cool systems

A reversible air-to-air heat pump does the same job as air conditioning in summer and heats the room in winter. GOV.UK lists a £2,500 Boiler Upgrade Scheme grant towards an air-to-air heat pump. You must own the property and be replacing fossil fuel heating, such as gas, oil, LPG or electric heaters, and the installer must be MCS certified to claim it for you. Cooling-only units don’t qualify, and the extra £1,500 for off-gas homes applies only to air-to-water and ground source heat pumps.

If you want to replace a boiler and radiators with a heat pump, that is a different job with a bigger grant. See our heat pump installation page and the Boiler Upgrade Scheme guide.

How to compare air con quotes

Put quotes side by side and check each one includes:

the make, model and cooling output in kW for each room, plus the refrigerant
pipe run length included, and the price per extra metre
brackets, trunking, core drilling, condensate drainage and making good
the electrical work, and whether it is certified
access costs such as scaffolding for a first-floor outdoor unit
warranty length, and whether it depends on a yearly service
the installer’s F-Gas company certification and the engineer’s own qualification

Selectra notes that whether the outdoor unit is easy to reach is one of the biggest swings in price. A quote with no survey, no named model or a single lump sum is hard to compare and easy to pad. Most guides suggest getting at least three quotes.

When to book

Installers fill up fast once a heatwave is forecast, and Selectra says summer waits stretch to weeks. Booking a survey in spring or autumn gives you time to sort freeholder consent and compare prices calmly. If you also want better ventilation for a stuffy flat, look at ventilation installation too, as air conditioning cools and dries the air but does not bring fresh air in.

Typical air conditioning installation prices

Job	Typical UK price	Notes
Single split, one room	£1,500 to £3,000	Labour is about £700 to £1,200 of this
Multi-split, two rooms	£3,200 to £4,500	One outdoor unit, two indoor heads
Multi-split, three or four rooms	£3,500 to £8,000	Sources range from £3,500 to £7,000 and £4,000 to £8,000
Ducted whole-home system	£6,000 to £20,000	Usually only practical in a new build or major refurb
Running a split	About 15p to 20p an hour	Roughly half the cost of a portable at about 26p to 35p an hour
Boiler Upgrade Scheme grant	£2,500 off	Air-to-air heat pumps that replace fossil fuel heating, in England and Wales

Sources: Selectra air conditioning cost and running cost guides (October 2026), Bestbuilders (June 2026), GOV.UK Boiler Upgrade Scheme. Selectra says London and the South East run 20% to 30% above these figures.

Air conditioning installation by city

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Scotland

Wales

Northern Ireland

Belfast

Common questions

How much does it cost to install air conditioning in one room?

Most fitted single split systems for one room cost £1,500 to £3,000 in 2026, according to Selectra. The price rises if the outdoor unit needs scaffolding, a long pipe run or a new electrical circuit. Expect the top of the range in London and the South East.

Can I install a split air conditioner myself?

Not legally on your own if the job involves handling refrigerant. GOV.UK says anyone who installs, services or recovers refrigerant from air conditioning needs their own F-Gas qualification. Some pre-charged units connect without opening the gas circuit, but you still need someone qualified to commission and service most systems, and many installers will not take on a DIY install.

Do I need planning permission for air conditioning?

In England, an air-to-air heat pump that heats as well as cools can fall under permitted development, so it often needs no planning application. Richmond Council's 2026 guidance says the unit must not be used solely for cooling, must be no larger than 1.5 cubic metres on a house, and a non-detached house can have only one unit. A cooling-only unit, a listed building or a unit nearer the road in a conservation area needs a planning check. Leaseholders usually need the freeholder's written consent before anything is fixed to the outside wall. Check with your council if you are unsure.

Is portable air conditioning cheaper to run than a split?

No. Selectra puts a portable at about 26p to 35p an hour and a split at about 15p to 20p an hour. The portable is smaller, but it works harder because warm air leaks back in around the hose.

Can I get a grant for air conditioning?

A reversible air-to-air heat pump, which heats and cools, can get a £2,500 Boiler Upgrade Scheme grant if it replaces fossil fuel heating such as gas, oil, LPG or electric heaters and you own the property. Cooling-only units get nothing. The installer must be MCS certified to claim it.

When is the best time to book an air con install?

Book outside summer. Selectra notes that waiting times stretch to weeks during hot spells and fall away at the end of the season, so a spring or autumn survey usually gets you fitted before the next heatwave.