Recognising when something’s wrong
A handful of symptoms cover most call-outs: the system runs but doesn’t cool effectively, ice forms on the indoor unit or pipework, water leaks from the indoor unit onto the wall or floor below, the unit makes a new grinding or rattling noise, or the display shows an error code. Each of these points towards a different likely cause — low refrigerant, a blocked drain, a failing fan motor, or a faulty sensor — and a competent engineer will diagnose before quoting rather than guessing.
What repairs typically cost
Straightforward issues such as a blocked condensate drain or a dirty filter causing poor airflow are often resolved within a single call-out, typically £80–£180 including labour. Refrigerant leaks are more involved, since UK regulations require the leak to be located and repaired before the system can be legally re-gassed, which usually runs £150–£400 depending on accessibility. Component failures — a fan motor, circuit board, or compressor — vary widely, from £150 for a straightforward part swap to £600 or more for compressor replacement, at which point it’s worth comparing against the cost of a new system.
Repair or replace?
As a rough guide, if a system is under seven years old and the fault is a single component failure, repair almost always makes financial sense. Between seven and twelve years old, it depends on the specific fault — a second or third refrigerant leak on an older system is often a sign the whole unit is degrading, and replacement may be more cost-effective over a few years than repeated repairs. Beyond twelve years, most engineers will be upfront that a repair is a short-term fix, since older refrigerants and parts availability both work against you.
Emergency versus scheduled repair
Most repair companies offer both same-day emergency call-outs, typically at a premium, and standard scheduled appointments within a few days at a lower rate. For anything beyond total system failure during extreme heat, a scheduled repair within the week is usually the more cost-effective choice.
Choosing a repair engineer
Anyone handling refrigerant — which covers the vast majority of repair work — is legally required to hold F-Gas certification. Ask to see this before any work begins, and check whether the engineer is familiar with your specific system brand, since some faults and error codes are manufacturer-specific.