Air Conditioning Installation Cost UK: Published Prices for One Room and a Whole Home

Estimate Your Cost

Tell it how many rooms, where the outdoor unit goes and what your fuse box is like. If you've had a quote, put it in and it'll tell you where it sits.

What We'd Budget

Our estimates, fitted, for wall-mounted units with the outdoor unit at ground level and a spare way in the fuse box. From OVO's (June 2026) and MyBuilder's (October 2026) published ranges; for a unit in each room we multiply the one-room figure and never go below the multi-split, because OVO says separate systems cost more. OVO and MyBuilder give one price band for 2 to 4 rooms, so those rows overlap.

Our view: if you want more than one room, a multi-split is the better buy. It's cheaper than a unit in each room. And in England and Wales, permitted development allows only one outdoor unit on a house that isn't detached (two on a detached house, one for a whole block of flats), so a second one means a planning application. A ducted system, hidden in the ceiling, is a different price bracket: OVO puts it at £8,000 to £15,000.

In England and Wales, a single-room outdoor unit won't trouble the permitted development size limit (1.5 cubic metres on a house; 0.6 on a block of flats in England, 1 in Wales), but we'd check a multi-split's bigger one.

Where Our Figures Come From

Two companies publish ranges by the size of the job, and our estimate is built from both. When we checked, on 25 October 2026:

Neither page quite agrees with itself. OVO's summary goes higher than its table (in brackets). MyBuilder's own breakdowns of a multi-split don't add up to its summary, so we use the summary. We take the widest spread: one room from every fitted one-room range above, then OVO's figure for each extra room, kept inside the published band for that many rooms. OVO's ranges include supply and fitting but not electrical upgrades.

These single prices are the ones we found, as a check on our ranges:

Glow Green's include VAT and fitting and say "around", so we've rounded them; BOXT's don't say whether VAT is included. The Energy Saving Trust and government figures are typical costs, not quotes. They come from different sources, which may be why the bigger home has the lower figure. The one-room prices for standard sizes sit inside our one-room range; Glow Green's bigger 5kW and 7.1kW units come out above it.

What Pushes the Price Up

• The size of the unit. Glow Green's 5kW Daikin was around £720 more than its 3.5kW.
• The pipe run. The further apart the indoor and outdoor units, the more pipe, and Daikin's Perfera needs extra refrigerant beyond 10 metres.
• Where the outdoor unit goes. High on a wall or on a roof can need scaffolding. There's no published figure for air con, so we use Octopus's as a guide: £800 to £1,000 is typical for the heat pump installs that need it.
• The electrics. Air conditioning needs its own circuit. If your fuse box has no spare capacity it may need an upgrade, which OVO says is usually a modest additional cost. If the whole fuse box needs replacing, we'd allow about £420 to £960, VAT included.
• Planning. In England and Wales a cooling-only unit needs planning permission, and a listed building or a unit on a wall facing the road can mean an application too. Scotland and Northern Ireland have their own rules. Our planning permission guide has a checker.

Expect one room to take half a day to a full day and a whole-home multi-split two to three days.

What to Ask an Installer

A quote is only comparable if it says the same things. We'd ask every installer:

• Which indoor and outdoor models, and what size? Without model names you can't compare quotes, or look up the efficiency. Ask how they sized it for the room.
• Does it heat as well as cool? If not, it needs planning permission, and it won't help in winter.
• How much pipe is included, and what each extra metre costs?
• What electrical work is included? A new circuit, and whether your fuse box needs replacing.
• Where will the outdoor unit go, and does it meet the permitted development rules?
• Are you F gas certified? They must be, by law, to connect the refrigerant pipes.
• Who makes good the wall where the pipes go through, and what's the warranty?

The Mistakes to Avoid

• Buying cooling only. It needs planning permission in England and Wales, it won't heat, and it's excluded from the grant. (Even one that heats won't usually give you hot water, so it doesn't replace a boiler on its own.) Mainstream wall units such as Daikin's Perfera heat as well, so we wouldn't buy one that doesn't.
• A separate unit in every room. It costs more than a multi-split, and in England and Wales a second outdoor unit on a house that isn't detached takes you outside permitted development.
• The wrong size. Too big and you've paid for capacity you don't use; too small and it runs flat out and still struggles on the hottest days.
• Buying a unit online, then looking for someone to fit it. It still needs an F gas qualified installer, and before selling equipment that isn't hermetically sealed, the seller has to ask who that will be.
• Comparing totals, not specs. The cheapest quote may leave out the electrics, the pipe or making good.

Should You Wait for the Grant?

Probably not. The Boiler Upgrade Scheme offers £2,500 towards an air-to-air heat pump in England and Wales. But only one that's designed to heat the whole home (MCS excludes systems that only cool), replacing fossil fuel or electric heating, in a home you own. And although gov.uk lists it, nobody can claim it yet. MCS says "no installers are yet certified to install air-to-air heat pumps", and the Energy Saving Trust said in October 2026 that you'll also have to wait for the scheme to open to these systems, which may not cover every type. Scotland's Home Energy Scotland scheme doesn't fund them.

Our view: if you want cooling for a room or two, don't wait, because you wouldn't qualify anyway. If you're planning to replace your heating with an air-to-air system for the whole home, waiting could save £2,500. The Energy Saving Trust says MCS expects certification before the end of 2026, but there's no date for the scheme opening to these systems. Our air-to-air heat pump guide has the full rules.

Can You Fit It Yourself?

No. A split system means connecting a refrigerant circuit, and it's against the law to work with F gas without the qualification: a category 2 certificate covers systems with less than 3kg. So a split system bought online still needs a qualified installer to connect it.

Split System or Portable?

A portable needs no installer and costs a fraction of a split system to buy, but it's far less efficient. Meaco's Cirro 12,000 BTU portable (about 3.5kW of cooling) draws 1,350 watts; Daikin's 3.5kW Perfera split gives similar rated cooling for about 756 watts, on its published efficiency. Our view: for a few hot weeks a year in one room, a portable is likely to be the cheaper choice overall. To heat with it too, or to cool a bedroom every night of a hot summer, we'd fit a split. Our running costs guide works out what each costs an hour.