The short answer
Most domestic air-con systems should be serviced about once a year. Busy, multi-unit or commercial systems often need servicing twice a year or more, because heavier use means faster dust build-up and wear. A service costs around £80–£150 per unit. Separately, larger systems carry a legal F-gas leak-check duty on a schedule set by the refrigerant charge — that is a distinct obligation from routine maintenance.
How often you service air conditioning depends on how hard it works and what the law requires. This guide sets out sensible intervals for homes and businesses, the factors that make a system need attention sooner, and the separate legal leak-check schedule for larger systems — so you neither over-pay for needless visits nor let a system silently lose efficiency.
Intervals at a glance
- Typical home About once a year
- Heavy or commercial use Twice a year or more
- Cost per visit £80–£150 per unit
- Filters Check monthly in heavy use
- Leak-checks Legal duty above set F-gas thresholds
- Driven by Usage, environment, charge size
The general rule: once a year
For a typical home, a single annual service is the sensible baseline. Air-con systems are most heavily used in summer, so the most common pattern is a service in spring, before the cooling season, so the system is clean and correctly charged when you need it. An annual visit is usually enough to keep filters and coils clean, the drain clear and the charge correct, and it satisfies most manufacturers’ warranty conditions. Many owners take out an annual maintenance contract to lock the visit in and get priority callouts — see what a service involves.
It helps to think of the annual service as the minimum that keeps the warranty valid and the system honest, not as the only maintenance that happens. Between services you do the light jobs — mainly checking the filters — while the engineer’s yearly visit handles the work you cannot safely do yourself, such as cleaning the internal coil, checking the refrigerant charge and inspecting the electrics. A system that gets neither the yearly professional service nor the in-between filter checks is the one that fails early and runs expensively, so the two halves work together.
When you need to service more often
The right interval is driven by how hard the system works and where it lives. Some situations call for two or more services a year.
- Year-round or heavy use — a reverse-cycle system that heats in winter and cools in summer runs far more hours.
- Commercial and multi-unit sites — offices, shops and server rooms run long hours and accumulate dust quickly.
- Dusty or coastal environments — building sites, busy roads and salty sea air foul coils faster.
- Health-sensitive spaces — where air quality matters, more frequent filter attention is wise.
| Use case | Suggested service interval |
|---|---|
| Domestic, occasional summer cooling | Once a year |
| Domestic, year-round heat and cool | Once or twice a year |
| Office / retail / commercial | Twice a year |
| Server room / continuous use | Two to four times a year |
Filters: the bit you check between services
Between professional services, the one job you can safely do yourself is checking the indoor filters. In a clean home, a glance every few months is fine; in heavy use or a dusty environment, check monthly. A clogged filter is the single most common cause of weak cooling and rising bills, and clearing it is easy — see maintenance tips. If cooling has dropped off, a dirty filter is the first thing to rule out before calling an engineer; see air con not cooling.
The separate legal leak-check schedule
Routine servicing and F-gas leak-checking are not the same thing. Under GB F-gas law, systems containing refrigerant above set thresholds must be leak-checked at fixed intervals — more frequently as the charge gets larger — by an F-Gas-certified engineer, with records kept. This duty falls mainly on larger and commercial systems, not a single small domestic split, but where it applies it is a legal requirement independent of how often you choose to service the equipment.
Getting the timing right
For most homes, book a service once a year, ideally in spring; for hard-working or commercial systems, twice a year; and check filters yourself in between. If your system is large enough to carry an F-gas leak-check duty, that schedule runs alongside — ask your installer to confirm what applies to your equipment. A useful prompt is to tie the booking to a fixed point in the calendar, such as the clocks changing or the start of spring, so it does not slip. If you cannot remember the last time the system was serviced, treat it as overdue and book one: an unserviced system that has been quietly losing efficiency for years will usually pay back the cost of a service in lower bills and a longer life. This page is general guidance, not a site-specific maintenance plan; a certified installer can set the right interval for your exact system and usage.
Time to book your annual service?
Get matched with an F-Gas-certified engineer who can service your system on the right schedule and keep it efficient, reliable and compliant.
Frequently asked questions
How often should home air-con be serviced?
About once a year is right for most homes, ideally in spring before the cooling season. Systems used year-round or heavily may need servicing twice a year.
How often should I check the filters?
Every few months in normal use, and monthly in heavy use or dusty conditions. A clogged filter is the most common cause of weak cooling.
Is a yearly service really necessary?
Usually yes. It keeps efficiency up, catches faults early and is often required to keep the manufacturer’s warranty valid. Skipping it tends to cost more later.
What is the F-gas leak-check schedule?
Larger systems must be leak-checked at intervals set by the refrigerant charge size, by a certified engineer. It is a legal duty separate from routine servicing.
Sources & further reading
- GOV.UK — F-gas: guidance for users, producers and traders
- The Fluorinated Greenhouse Gases Regulations 2015 (GB F-gas)
- Energy Saving Trust — running cooling efficiently
- REFCOM / F-Gas Register — leak-checking requirements
This guide is general information, not a site-specific survey or a substitute for a quote from an F-Gas-certified installer. Installation, servicing and refrigerant handling are legally restricted to F-Gas-certified engineers.