Air Conditioning · Updated August 2026
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.
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: Best Builders 2026 quote data across 519 UK towns.
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 |
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 |
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.
Repairs & faults — frequently asked questions
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.
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.
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.
You can clean filters and clear a drain. Anything touching the refrigerant circuit legally requires an F-Gas registered engineer.
Related air conditioning guides
Every system type priced side by side.
What it costs per hour and per summer.
When an external unit needs consent.
Reviewed by the BestBuilders editorial team on 9 August 2026 · Next scheduled review: November 2026 · See our editorial standards.