How much does air conditioning cost to install in a UK home?

If you have spent the last few summers lying in bed with a fan pointed at your face, there is a good chance you have wondered what it would cost to do the job properly.

The short answer

Most people asking this want one number. There is not one, and anybody who offers you a number before looking at your home is guessing.

What an installation costs is set by your rooms, your walls, and where the outdoor unit can reasonably go. Two houses on the same street can turn out to be quite different jobs.

What you are actually paying for

The unit itself is often the smaller part of the bill.

A proper quote normally accounts for:

• the indoor unit and the outdoor unit
• refrigerant pipework and cabling
• installation labour, usually a morning or two of careful work
• the electrical work
• brackets, mounting and making good afterwards
• commissioning, testing and handover
• how awkward the installation is

That last one moves the price more than people expect. A bedroom at the back of a detached house with an obvious spot for the outdoor unit is straightforward. A fourth-floor flat with restricted access and nowhere obvious for the outdoor unit is a different job.

Where the outdoor unit goes is worth checking properly rather than assuming. Distance to a boundary, a conservation area or a listed building can all affect what is sensible and what is allowed.

Does the size of the room matter

Yes, although floor area on its own is not enough to go on.

Bigger rooms generally need more capacity, but a good installer will also look at:

• how much direct sunlight the room gets
• window size and glazing
• insulation
• ceiling height
• how many people normally use the room
• whether it is a bedroom, kitchen, office or living area

This is why buying the biggest unit you can find is not a shortcut. An oversized system cools in short bursts and then switches itself off, which is noisier, less comfortable and no cheaper to run. A correctly sized one holds the temperature quietly and gets on with it.

One room, or several

Cooling several rooms costs more, but not in a straight line.

Rather than a separate outdoor unit for every room, a multi-split system lets one outdoor unit serve several indoor units. That tends to suit homes that want:

• the main bedroom
• a second bedroom or a nursery
• a loft conversion or a home office

It also keeps the outside of the house tidier, which matters more than you might think when the alternative is three outdoor units on one wall. If bedrooms are your starting point, our guide to bedroom air conditioning goes through noise and placement in more detail.

Every system we spec heats as well as cools

This is the part most cost comparisons miss. The systems we spec are reversible air-to-air heat pumps. They cool the room in summer and heat it in winter, using the same equipment.

We never spec cooling-only units. A cooling-only box sits idle for nine months of the year and gives up the heating side entirely.

For a loft conversion, home office, garden room, or a bedroom you would rather not fire up the whole central heating system for, running one efficient unit in one room is usually the sensible option. If you are still deciding, start with is air conditioning worth it in the UK.

How to get an accurate figure

The quickest route is a price built from your own property rather than a national average.

Your postcode, the rooms you want to cool, rough room sizes and a couple of photos tell an experienced installer a great deal before anyone needs to visit. Photos are optional. Answer the questions on their own and you still get an estimate, just a wider one.

And no, you should not have to spend half an afternoon on the phone to find out whether this is remotely within budget.