A refrigerant system is a sealed circuit and a pair of heat exchangers, and almost everything that degrades its performance is dirt. Filters clog, the outdoor coil fills with dust and blossom, the condensate tray silts up, and the compressor works longer for the same result. A service is mostly cleaning, and it is the cheapest performance gain available to any existing system.
What air con servicing covers at each visit
Filters cleaned or replaced, indoor coil and blower checked, outdoor coil cleaned, condensate tray and drain cleared and the pump tested if there is one, electrical connections checked, refrigerant pressures and temperatures measured against the expected values, controls and fault history read, and the whole thing recorded. That record is what the manufacturer will ask to see.
How often air conditioner maintenance is needed
Once a year is the normal domestic interval, ideally in spring before the season it is needed. Systems that also heat are working all year and are worth doing at the same annual point regardless. Where a system is in a dusty environment or runs continuously, twice a year is the usual answer and the installer should say so at handover.
AC unit maintenance you can do yourself
Filters. Most indoor heads have washable filters behind a hinged front panel, they take minutes, and they are the single biggest airflow variable. Keeping the outdoor unit clear of leaves, shrub growth and stacked garden furniture is the other one. Anything involving the refrigerant circuit or the electrics is not a homeowner task.
Why the record matters
Manufacturer warranties are conditional on servicing at the stated interval by a suitably qualified person, and the evidence is the record rather than your memory. A system with an unbroken service history is also worth more when a house is sold, in the same way any other piece of building plant is.
Questions people ask about air conditioning maintenance
Does a domestic system legally need servicing?
There is no general legal requirement to service a small domestic system, though there are legal duties around refrigerant handling and, above certain charge sizes, leak checking. The practical drivers are the warranty condition and the running cost, both of which point the same way.
How much does an air conditioning service cost?
It is priced per visit and per indoor unit, so a multi split with three heads costs more than a single system. Most installers offer an annual plan that is cheaper than an ad hoc visit and usually includes a response time, which is the part worth reading.
Can I use a different firm from the installer?
Yes, provided they hold the right certification, and it is worth asking whether the manufacturer requires an accredited installer to preserve the warranty. Bring the commissioning sheet and the previous service records to the first visit.
What happens if I never service it?
It will keep running and slowly get worse: longer run times, higher bills, and a greater chance of the condensate route blocking and putting water somewhere it should not be. Then it fails outside warranty because the warranty condition was not met.