Air Conditioning Repair

Air conditioning almost never fails in April. It fails on the hottest afternoon of the year, in a top-floor flat, with a bedroom that is already at twenty-nine degrees — which is exactly when every engineer in London is fully booked and half of them are not answering the phone.

That is the situation this page is written for. Below is what typically goes wrong and why, what an air conditioning repair realistically costs in London, and how to tell the difference between a system worth fixing and one worth replacing.

Most callouts across London come down to the same handful of problems. Recognising the symptom will not fix it, but it does tell you how urgent it is.

Running, but not cooling

Usually low refrigerant from a leak, a clogged filter or coil, or a failed capacitor stopping the outdoor fan. Almost never a matter of the unit being 'set wrong'.

Water dripping from the indoor unit

A blocked condensate drain nine times out of ten — algae and dust building up in the line until the tray overflows. Quick to fix, expensive if ignored while it soaks a wall.

Ice on the pipework or indoor unit

Restricted airflow or low refrigerant charge. Turn the system off and let it defrost before we arrive; running it iced up risks the compressor.

Error code on the display or flashing lights

The system is telling us where to look. Note the code down before you reset it — that code often saves an hour of diagnosis time and cuts your bill.

Tripping the electrics

A failing compressor, a damaged cable, or moisture in the outdoor isolator. This one is worth switching off at the isolator and calling promptly.

Loud rattling, grinding or humming

Fan bearings, a loose panel, or debris in the outdoor unit. Grinding from the compressor is the serious version and should not be run through.

One thing worth knowing before anyone quotes you: air conditioning is a sealed system, so it does not consume refrigerant. If a unit is low on gas, there is a leak. Under the government's F-Gas rules on refrigerant handling that leak has to be traced and repaired, not simply topped up each summer — and any engineer offering a routine annual refill is selling you the same problem twice.

Six steps from your phone call to a working system, with a price agreed before anyone picks up a tool.

1. 01

   Phone triage

   Describe the symptom and any error code on the display. Half the time we can tell you what it probably is, and what it will likely cost, before we leave.

2. 02

   Attendance

   Same day across London where an engineer is free, next working day otherwise. You get an arrival window, not a whole-day wait.

3. 03

   Diagnosis

   Electrical readings, refrigerant pressures, sensor resistances and fault history from the control board — measured, not guessed.

4. 04

   Fixed repair price

   We tell you what's wrong, what it costs and how long it will last before we touch anything. You decide from there.

5. 05

   Repair

   Most common faults are fixed on the first visit. Where a part has to come in, we order it that day and book you back in.

6. 06

   Test and report

   System run through its full cycle, readings recorded, and any second issue we spotted flagged so it doesn't surprise you later.

Callout and diagnosis

Typically £90 to £150 including VAT, covering the visit and a proper diagnosis rather than a guess. That charge comes off the repair if you go ahead with it, so you are not paying twice.

Common repairs

Most everyday fixes — a run capacitor, a contactor, a fan motor, a blocked condensate drain, a failed sensor — land somewhere between £150 and £400 including parts, labour and VAT. These are the repairs that get done on the first visit.

Leak detection and recharge

More involved, because it is done properly rather than quickly: trace the leak, repair it, pressure test, evacuate, then recharge to the manufacturer's weight. Expect a range rather than a single figure until we know where the leak is, and expect two visits on anything but the simplest case.

Compressor failure

The one genuinely bad outcome. On a system under warranty it is usually covered. Out of warranty, the part and labour frequently approach the cost of a new system, at which point replacing the unit buys you a much more efficient system and a fresh warranty for similar money. We will show you both numbers and let you choose.

There is no universal answer, but there is a workable rule of thumb we apply on every visit:

• Under eight years old: repair. The system has plenty of life left and parts are readily available.
• Eight to fifteen years: it depends on the fault. A capacitor is worth fixing on a twelve-year-old unit; a compressor probably is not.
• Over fifteen years, or running on R22: replace. R22 refrigerant has been phased out, so those systems cannot legally be recharged, and a modern equivalent will use substantially less electricity for the same cooling.

We would rather tell you a system is finished than take money for a repair that buys you one more summer. If replacement is the honest answer, the installation cost guide sets out what a new system actually costs in London.

We are REFCOM registered and F-Gas qualified, which is a legal requirement for anyone opening a refrigerant circuit and a reasonable thing to check on any engineer you let near your system. We carry the common failure parts on the van so most faults are fixed on the first visit. And every air conditioning repair is quoted at a fixed price before we start, so the conversation at the end is about the system rather than the invoice.

Once you are back up and running, the cheapest thing you can do is book an annual service — most of the breakdowns we attend in July were visible as a problem in March.