Air Conditioning Installation Costs in the UK (and How to Actually Find a Good Installer)

Type “air conditioning installation” into Google and you’ll get eleven near-identical local firms, each with a stock photo of someone in a polo shirt holding a spanner, and not one visible price. That’s not an accident — it’s a quote-funnel industry, and it works precisely because most people go into it not knowing what a fair price looks like or what a legally competent installer is actually required to have. This guide exists to close both of those gaps before you pick up the phone.

What it actually costs

Ignore the single “average cost” figure most sites lead with — it’s an average across wildly different jobs, so it tells you almost nothing about your own. What matters is which category you’re in:

A single room, one indoor unit, one outdoor unit — this is the job most people asking about “domestic air conditioning” actually mean. Fully fitted, expect £1,500–£3,000, made up of roughly £600–£1,400 for the unit itself and £700–£1,200 for labour. Anyone quoting you a single number without splitting those two out is making comparison shopping harder than it needs to be, deliberately or not.

Multiple rooms off one outdoor condenser (multi-split) — £2,800–£7,000, depending on how many indoor units and how far the pipework has to run.

Whole-house ducted systems — a genuinely different scale of job, £6,000–£15,000, closer to a small renovation than an appliance purchase.

Add roughly 20–30% to all of the above if you’re in London or the South East. That’s not an installer marking you up specifically — it’s the regional labour market, and it shows up in every trade, not just this one.

The one thing that actually matters before you hire anyone

Forget star ratings for a second. Legally, anyone installing, servicing, or decommissioning a system containing F-Gas refrigerant — which is to say, any domestic air conditioner — has to hold specific qualifications, and their company has to hold a REFCOM (or equivalent) F-Gas company certificate. This isn’t a nice-to-have accreditation like a “trusted trader” badge; it’s the law, enforced with fines up to £200,000 per offence for companies that skip it.

So ask. A legitimate installer will produce their company’s F-Gas certificate without hesitation, because they have to have it anyway. One who gets vague, changes the subject, or tells you “we’re sorting that out” is not somebody to let near your gas-filled equipment, whatever their Google reviews say.

Beyond that, the boring-but-correct advice still holds: get three quotes, itemised the same way (unit, labour, any additional pipework or electrical work), and read reviews on an independent platform rather than whatever’s pinned to the top of their own homepage. If you’d rather not do that legwork yourself, a vetted tradesperson platform such as RatedPeople can shortlist pre-checked local installers for you — a genuine time-saver, though it doesn’t replace confirming the certificate yourself once you’re comparing real quotes.

This guide is here to help you ask the right questions and spot a fair price — it isn’t a substitute for the installer’s own assessment of your property, and the actual installation should always be carried out by a properly certified professional. See our disclaimer for the full picture.

The planning permission catch nobody explains properly

Most advice on this stops at “check with your council,” which is true but unhelpfully vague. Here’s the actual rule for houses in England: a single split-system unit is usually permitted development — no planning application needed — if the outdoor unit is under 1.5 cubic metres, sits at least a metre from the boundary, isn’t mounted on a wall facing a road above ground-floor height, and the property isn’t listed, a flat, or in a conservation area.

There’s a twist buried in that rule that changes the calculus for a lot of readers: it only applies to reversible systems that provide heating as well as cooling. A cooling-only unit needs planning permission regardless of size or placement, full stop. Which means the air-to-air heat pump most of this site’s advice already points you toward for its running costs and grant eligibility also happens to be the version that’s far more likely to avoid a planning application entirely — not a coincidence worth ignoring when you’re comparing systems.

If you’re in a flat, the limit drops to 0.6 cubic metres and in practice most external units will need permission regardless of what they contain. Conservation areas, listed buildings, and properties with an Article 4 direction can lose permitted development rights altogether — always confirm with your local planning authority before an installer shows up, not after.

Where this fits against everything else on this site

If you haven’t ruled out simpler options yet, our comparison of portable AC, split systems, evaporative coolers and fans is the honest starting point — a full installation is a genuine commitment, not something to default into because a Google ad got there first.