Air Conditioning

Air Conditioning Repair Cost UK 2026

Most AC faults are small and cheap; a few are terminal. Call-out and diagnosis runs £90–£150, common repairs £150–£450, and a failed compressor on an older unit usually means replacing rather than repairing.

£90–£450 typicalCall-out £90–£150Same or next day

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The numbers

Air conditioning repair cost by fault — 2026

Diagnosis is usually charged separately and often credited against the repair.

Fault	Typical cost	Symptom
Call-out & diagnosis	£90–150	Charged first, often credited against the repair
Refrigerant leak repair & regas	£200–450	Cools weakly, ices up, runs constantly
Condensate drain blockage	£90–180	Water dripping from the indoor head
Sensor or thermistor	£120–250	Wrong temperature, short-cycling
Fan motor (indoor or outdoor)	£180–400	Noisy, rattling, or no airflow
Control PCB	£250–450	Unit dead or unresponsive to the remote
Compressor	£450–900+	Usually replace the unit instead on anything over ~8 years

Source: BestBuilders’ 2026 regional cost model (national cost guides × regional labour index), averaged across 519 UK towns.

The economics of a repair hinge on the unit’s age: on a system past roughly eight years, a compressor or control-board failure often costs more than a like-for-like replacement once refrigerant and labour are added, so a fresh, more efficient split can be the cheaper decision over its remaining life. Many faults are also preventable — blocked drains, fouled coils and slow refrigerant loss are exactly what a yearly visit catches, so it is worth weighing this bill against our air conditioning servicing cost guide. If replacement wins out, our split air conditioning cost guide sets out what a new single-room system runs in 2026.

What moves the price

What changes the cost

Cost factor	Typical impact	Why it matters
Pipe run length	+£150–400	Runs over ~5m need extra refrigerant pipe, insulation and labour; long vertical runs in flats cost most
Condenser siting & access	+£100–600	Ground level next to the room is cheapest; roof, height or scaffold access adds cost
Number of indoor units	+£700–1,500 each	Each extra head adds unit, pipework and commissioning time
Electrical work	+£150–500	A dedicated spur, consumer-unit way or isolator may be needed
Capacity (kW / BTU)	+£200–1,200	Oversizing wastes money up front and on running cost
Brand & range	+£400–800	Premium Daikin/Mitsubishi designer ranges vs value Samsung/LG
Making good	+£0–300	Trunking, core-drilling, plaster patching or repainting around the route

By region

Air conditioning cost by UK region — 2026

Labour rates and access drive most of the regional spread. Figures below are for a single-room split; the same percentages apply across the other system types.

Region	Single-room split (installed)	vs UK average
London	£1,900–3,600	+25–30%
South East	£1,750–3,300	+15–25%
South West & East	£1,550–3,000	+5–10%
Midlands	£1,450–2,800	Baseline
North of England	£1,400–2,700	−5%
Wales & Scotland	£1,400–2,750	−5% to baseline

How it works

Getting it priced properly

1. Size it first

Capacity comes from room size, glazing and aspect — not from guesswork. An installer who quotes without asking about the room is guessing.

2. Check F-Gas registration

Anything touching the refrigerant circuit legally requires an F-Gas registered engineer. Ask to see it and check it on the register.

3. Compare like for like

Get three itemised quotes covering the same capacity, brand tier and pipe run, so you are comparing the job and not the wording.

Visual guide

Repairs & faults costs compared

Where this job sits against the other air conditioning jobs, on 2026 UK prices. Your own quote depends on size, access and spec.

Source: BestBuilders 2026 pricing across 7 air conditioning jobs. The highlighted bar is this page.

Common questions

Repairs & faults — frequently asked questions

Is it worth repairing an old air conditioner?

Below about eight years, almost always. Beyond that, if the compressor has failed, the repair often costs more than half a new installed unit — and a new one will be markedly cheaper to run, so replacing is usually the better call.

Why does my AC need a regas?

A sealed system should never need topping up. Needing refrigerant means there is a leak, so a regas without finding and fixing the leak is money thrown away — and venting refrigerant is an offence.

Why is water dripping from the indoor unit?

Almost always a blocked condensate drain, which is one of the cheaper fixes at £90–180. Left alone it will damage the wall and the unit.

Can I repair it myself?

You can clean filters and clear a drain. Anything touching the refrigerant circuit legally requires an F-Gas registered engineer.

Keep reading

Air conditioning cost 2026

Every system type priced side by side.

Running costs

What it costs per hour and per summer.

Planning permission

When an external unit needs consent.

Go deeper

Repairs & faults — guides and detail

The detail behind the number: what changes the price, the planning position, and how to check a quote before you accept it.

AC repair cost calculatorPrice the fault by symptom, with a repair-or-replace steer.See costs & get quotes →

Registered members: Air Conditioning

7 businesses offering air conditioning have a public profile with BestBuilders. Each listing is a business that registered with us directly; the details shown are the ones it declared at registration, and a Companies House number appears only where one was given.