What happens at an air conditioning service

A yearly service is mostly cleaning and checking. Done in April or May, before the warm spell, it keeps a unit quiet, dry inside and working as efficiently as it was designed to. This is what one of our services covers.

Inside: filters, coil and drain

The filters come out and are washed. The coil behind them is cleaned so air passes freely, and the condensate drain is flushed through, because a blocked drain is the usual reason a unit drips water into the room.

Outside: the outdoor unit

Leaves, dust and cobwebs are cleared from the fan and the outdoor coil. We check the brackets or stand, the pipe insulation and the electrical connections.

The refrigerant check

We check the system’s pressures and look for signs of a leak at the joints. In Great Britain, only an engineer who holds an F-gas certificate may work on the refrigerant circuit.

Is it a legal requirement?

For larger systems, regular leak checks are. Under the F-gas rules in Great Britain, equipment holding F gas equal to 5 tonnes of carbon dioxide or more must be checked for leaks at least every 12 months, or every 24 months where an automatic leak detection system is fitted, and more often above 50 tonnes. Most single-room home units hold less than that, so for them a yearly service is good care rather than a legal duty.

The paperwork

One page for your files: the work done, the pressures and temperatures measured, and a note of any part starting to wear.

Sources: GOV.UK, “Checking F gas equipment for leaks” and “Qualifications to work with F gas” (both read 4 November 2026).