Prices for air conditioning vary a lot, and the reasons are rarely the ones people assume. It is not usually the brand, and it is not usually the installer's hourly rate. It is pipe run length, condenser access, electrical work and how honestly the system was sized in the first place.
This guide sets out real London figures for 2026, breaks down what drives them, and shows you how to compare three quotes that look different on paper. It is written to be read before you start collecting prices, not after you have already picked one.
Prices last reviewed: October 2026.
Quick answer: what does AC installation cost?
- One room: £1,800 – £2,600 for a 2.5kW split, or £2,200 – £3,000 for a 3.5kW.
- One large room: £2,600 – £3,700 for a 5kW unit, or £3,000 – £3,900 for a 7kW unit.
- Two rooms: £3,500 – £5,000 on a multi-split with one outdoor unit.
- Three rooms: £4,800 – £6,500.
- Whole house (four to five rooms): £6,500 – £9,500.
All figures include the equipment, labour, a standard pipe run, commissioning and VAT. The extras that can sit on top are listed further down.
System prices at a glance
| System | Typically suits | Installed price |
|---|---|---|
| Single split — 2.5kW | Bedroom, home office, small study | £1,800 – £2,600 |
| Single split — 3.5kW | Living room, large bedroom, loft conversion | £2,200 – £3,000 |
| Single split — 5kW | Large living room, kitchen-diner | £2,600 – £3,700 |
| Single split — 7kW | Open-plan ground floor, large through-lounge | £3,000 – £3,900 |
| Multi-split — 2 rooms | Two indoor units, one outdoor condenser | £3,500 – £5,000 |
| Multi-split — 3 rooms | Typical London terrace or three-bed flat | £4,800 – £6,500 |
| Multi-split — 4 to 5 rooms | Whole-house cooling in a family home | £6,500 – £9,500 |
| Ducted / concealed | Period property or high-spec refurbishment, per zone | £4,000 – £6,000 |
The pattern to notice: the jump from one room to two is large, and every room after that is comparatively cheaper. That is because a multi-split shares one outdoor condenser and one set of external services across all the indoor units. If there is any chance you will want a second room cooled within a few years, it is substantially cheaper to specify the condenser for it now than to add a second outdoor unit later.
Cost by type of home
If you would rather start from the house than the kW rating, these are the same ranges grouped by the jobs we see most often.
| Home | Typical job | Typical cost |
|---|---|---|
| Flat — one room | Usually the main bedroom; access for the outdoor unit is the big variable | £1,800 – £3,000 |
| Terraced house — two rooms | Two bedrooms on a multi-split, outdoor unit in the back garden | £3,500 – £5,000 |
| Semi-detached — three rooms | Bedrooms plus a living room or loft conversion | £4,800 – £6,500 |
| Detached house — four to five rooms | Whole-house cooling, often with concealed pipework | £6,500 – £9,500 |
Flats have the widest range for a single room because of the outdoor unit. A ground-floor flat with a garden is as simple as a house. A top-floor flat where the only position is a high rear wall may need access equipment, and the freeholder usually has to agree to it first.
Want the real number rather than a range? The survey is free and there's no obligation.
Get a fixed priceThe costs that sit outside the headline price
These are the items that turn a competitive-looking quote into an expensive one after work has started. A good quote either includes them or tells you plainly that it does not.
| Item | When it applies | Typical cost |
|---|---|---|
| Scaffolding or access equipment | Where the condenser can't be reached safely from a ladder | £400 – £900 |
| Extra pipe run | Beyond the standard 3–5m included in most quotes, per metre | £30 – £60 |
| New electrical circuit | Dedicated supply from the consumer unit, including certification | £200 – £450 |
| Condenser mounting | Wall brackets, anti-vibration feet or a ground-level plinth | £150 – £300 |
| Making good and decorating | Filling and finishing core-drilled holes and chased runs | £100 – £300 |
| Removing an old system | Refrigerant recovered and old units disposed of legally, when replacing | £150 – £350 |
| Annual service | Required to keep the manufacturer warranty valid, per year | £90 – £140 |
What actually drives the price up or down
Distance between the indoor unit and the condenser
This is the single biggest variable and the one homeowners rarely think about. Refrigerant pipework is expensive, and running it neatly through a finished house is slow work. A rear bedroom with the outdoor unit directly below is a straightforward job. The same unit in a front bedroom, with the condenser at the back of the house, can add a day of labour and a meaningful materials bill.
Where the outdoor unit can go
Ground level with clear access is best. Flat roofs, balconies, light wells and anything above the first floor may need scaffolding or a tower, which is a fixed cost regardless of how quick the actual installation is. In conservation areas the position may also be constrained by what is acceptable from the street — the Planning Portal's guidance on domestic air conditioning sets out the permitted development conditions, and a householder planning application where one is needed adds both a fee and several weeks.
Electrical work
Most systems need their own circuit run from the consumer unit. If your board is modern with a spare way and sits near the condenser position, this is a couple of hundred pounds. If it is a full board with no spare capacity, or a long way from where the unit needs to go, it costs more — and that difference is a common reason two quotes diverge.
Building fabric and finish
Core drilling a solid Victorian wall takes longer than a modern cavity. Concealing pipework inside a finished room costs more than running it in external trunking, and looks far better. Period London properties tend to sit at the higher end of every range on this page for exactly these reasons.
Equipment choice
Brand matters less than people expect — Daikin, Mitsubishi Electric, Panasonic, LG and Samsung all make good equipment, and published manufacturer specifications let you compare efficiency ratings and sound levels directly. What genuinely changes the price is capacity and indoor unit style: a slim ducted or concealed unit costs considerably more than a standard wall-mounted one doing the same job.
Replacing an existing system
Replacing an old unit costs about the same as fitting a new one of the same size, plus £150 to £350 to recover the refrigerant and dispose of the old equipment legally. Refrigerant must be recovered by a qualified engineer and can't be vented. Replacement is sometimes cheaper than a first installation because the hole through the wall, the electrical circuit and the condensate drain already exist.
Whether the old pipework can be reused depends on its size, its condition and the refrigerant the new unit uses. We pressure-test it before deciding. If it fails, or is the wrong size, new pipe is the only safe option. Before you replace anything, it is worth checking that a repair isn't the cheaper answer. We will tell you honestly if it is.
How to compare three quotes properly
If you get three prices back and they are hundreds of pounds apart, they are almost certainly not describing the same installation. Ask each installer for these five things in writing:
- The capacity of each indoor unit in kW, and the heat load calculation behind it. An undersized unit is cheaper to buy and will never keep the room comfortable.
- The pipe run length included, and the rate for anything beyond it.
- Whether electrical work is included or listed as provisional.
- Whether making good is included — that is, whether they fill and finish the holes they drill.
- Their F-Gas registration. Anyone handling refrigerant must be qualified; if that cannot be produced quickly, stop there.
Once all three quotes answer those questions, the comparison usually becomes obvious — and the cheapest one often stops being the cheapest.
Running costs and ongoing spend
A 3.5kW living-room unit draws roughly 1kW when working hard, which at current London electricity prices is somewhere around 25 to 35 pence an hour. Inverter systems then modulate down substantially once the room reaches temperature, so a full day of use rarely costs what a straight multiplication suggests. Across a typical British summer, most households find the seasonal running cost is a smaller number than they braced for.
The predictable ongoing cost is maintenance: an annual service at £90 to £140 per system. It is not optional in practice, because virtually every manufacturer makes it a condition of the five to seven year warranty.
Worth knowing: almost every system on this page heats as well as it cools, and does so efficiently. If lower heating bills rather than summer comfort is your real objective, read the air-to-air heat pump cost guide — it compares running costs with gas and electric heaters.
Prices in Sutton, Wallington and South London
We are based in Wallington, and the figures on this page are the ones we quote across South London and North Surrey. Distance doesn't change the price. The house does. If you are in the borough, see air conditioning in Sutton or air conditioning in Wallington for what we look for in local homes, from Carshalton terraces to Worcester Park semis, or air conditioning in Croydon next door.
Questions
Frequently asked questions
What is the installation charge for air conditioning on its own?
Most London installers, us included, quote supplied-and-fitted rather than a separate labour rate, because the fitting work depends on the system that is going in. As a guide, labour, pipework, commissioning and certification make up roughly a third to a half of a single-room price; the equipment is the rest. Be wary of a low day rate with the pipe, electrics and commissioning listed separately: that is where a cheap-looking quote grows.
How much does it cost to install air conditioning in a London flat?
For one room, budget £1,800 to £2,600 for a 2.5kW split system supplied, fitted and commissioned. Flats carry two extra variables that houses often don't: where the outdoor condenser can legally and practically go, and whether the freeholder will consent to it. A balcony or flat-roof position that needs access equipment can add several hundred pounds, and freeholder consent can add weeks to the timeline even when it costs nothing.
How much does a 7kW air conditioner cost to install?
Typically £3,000 to £3,900 supplied, fitted and commissioned in London. A 7kW unit is the size for a large open-plan room, such as a knocked-through ground floor or a big kitchen-diner. Check that the size comes from a heat load calculation rather than a guess: a 7kW unit in a room that only needs 5kW costs more to buy and switches on and off more often, which wears it faster.
How much does it cost to replace an air conditioning unit?
Budget roughly what a new system of the same size costs, plus £150 to £350 to recover the refrigerant and dispose of the old units legally. The saving, where there is one, comes from reusing the existing route: the holes are already drilled and the circuit is already there. Old pipework can sometimes be reused if it is the right size and passes a pressure test, but we only do that when it is genuinely sound.
Why are quotes for the same job so different?
Usually because they aren't the same job. Check three things on every quote: the capacity in kW of each indoor unit, the pipe run length included before extras kick in, and whether electrical work, commissioning and making good are inside the price or listed as provisional. A quote that omits any of those isn't cheaper — it's less complete, and the difference reappears as a variation once work has started.
Is it cheaper to install air conditioning in winter?
Often, yes, and it is always easier. Installers are busiest from late May to August, when slots fill up and some firms stop offering discounts. Between October and March you can usually choose your installation date, and any building work, freeholder consent or planning application has time to happen before you need the cooling.
Is air conditioning expensive to run in London?
Less than most people expect. A 3.5kW living-room unit typically draws around 1kW while cooling, which at current London electricity prices works out at roughly 25 to 35 pence an hour — and modern inverter units drop well below full draw once the room reaches temperature. Realistically, most households run their system hard for perhaps six to eight weeks a year, which keeps the annual cost modest.
Does air conditioning add value to a London property?
It's rarely a pound-for-pound return, but it is increasingly expected in higher-value London flats, top-floor conversions and new-build apartments where summer overheating is a known problem. A discreet, properly installed multi-split with concealed pipework reads as a specification upgrade; visible trunking running down a front elevation does the opposite. Installation quality matters more to value here than the brand on the unit.
Can I get a grant towards air conditioning?
No. The Boiler Upgrade Scheme only covers air-to-water heat pumps that replace a boiler, claimed through an MCS certified installer. Split systems — which heat as well as cool — aren't eligible from any installer. Our air-to-air heat pump cost guide explains the running costs for heating.
How long does the whole process take?
From first call to a working system, usually two to four weeks. That's typically a few days to arrange the survey, a couple of days to prepare the quote, one to two weeks for equipment to arrive, and one to three days on site depending on how many rooms are involved. Freeholder consent or a planning application will extend that, which is why we identify those at survey stage rather than after ordering.