How often should air conditioning be serviced?
Once a year for most homes, twice if the unit heats as well as cools, and two to four times a year for commercial systems — with fixed F-Gas leak-check and TM44 intervals on top for larger installations. The schedule by system type, and why.
Recommended service intervals by system
| System | Recommended frequency | Driver |
|---|---|---|
| Domestic single split, summer cooling only | Once a year (spring) | Efficiency, hygiene, warranty |
| Domestic split also used for heating, or heavy use | Twice a year (spring + autumn) | Double the running hours |
| Domestic multi-split or ducted whole-house | Once or twice a year | More indoor units and ductwork |
| Small office / shop (under 12 kW) | 2 visits a year | Long daily run hours; duty of care |
| Larger commercial, restaurant, server room, VRF | 3–4 visits a year | Critical cooling; F-Gas leak checks; TM44 every 5 years above 12 kW |
Manufacturer guidance and typical UK maintenance-contract schedules, 2026. Visits typically cost £75–£150 per unit (servicing cost guide).
Domestic systems: annually, or twice if it heats too
For a wall-mounted split that cools a room in summer, one full service a year is enough — book it in spring so the unit enters the hot months with clean coils, a clear drain and confirmed refrigerant pressures. Between visits, rinse the filters every month or two and keep the outdoor unit clear.
Modern units are air-to-air heat pumps and many households now run them for winter heating too, doubling the running hours. For those systems — or units in dusty or pet-heavy homes, or anywhere the unit runs most days — a second visit in autumn is money well spent, and two visits a year is the usual shape of a domestic maintenance contract. Every visit should be documented: annual servicing is usually a condition of the warranty.
Commercial systems: two to four visits a year
Offices, shops, restaurants and server rooms run their air conditioning far longer each day than a home, often year-round, and a failure costs trade rather than comfort. Two to four planned visits a year is the norm: two for a small office with a couple of splits, quarterly for larger VRF systems, kitchens and anywhere cooling is critical. Commercial operators also pick up the two legal obligations below, which a good provider builds into the schedule. See our commercial air conditioning page for how maintenance is priced per site.
F-Gas leak-check intervals: set by refrigerant charge
Under the UK F-Gas regulations, equipment containing fluorinated refrigerant above certain thresholds must be leak-checked at fixed intervals by a certified engineer, and the checks logged. Thresholds are in tonnes of CO2 equivalent (charge in kg × global warming potential).
| Refrigerant charge (CO2e) | Typical minimum leak-check interval | With a fixed leak-detection system |
|---|---|---|
| Under 5 tonnes | No mandatory interval | — |
| 5 tonnes and above | Typically every 12 months | Typically every 24 months |
| 50 tonnes and above | Typically every 6 months | Typically every 12 months |
| 500 tonnes and above | Typically every 3 months | Typically every 6 months |
Based on the retained F-Gas regulation as applied in Great Britain; hermetically sealed equipment under 10 tonnes CO2e is typically exempt. Your maintenance provider should confirm what applies to your equipment.
A single-room domestic split on R32 (GWP 675) holds well under 5 tonnes CO2e, so no legal leak-check interval applies; a large multi-split or VRF system, or an older high-GWP system, can cross the 5- or 50-tonne lines. Our F-Gas certification guide explains who may carry out this work.
TM44 inspections: every five years above 12 kW
Separately, the Energy Performance of Buildings regulations require air conditioning with an effective rated output above 12 kW to have an energy inspection by an accredited assessor at least every five years, to the CIBSE TM44 methodology, lodged on the national register. It is a legal duty on the building owner or operator. The 12 kW threshold is the combined output of all systems in a building, so several small splits across an office can add up to an obligation; homes are very rarely affected.
Manufacturer warranty conditions
The schedule most homeowners actually need to meet is the one in their warranty. Standard warranties on domestic splits are typically conditional on annual servicing by a qualified engineer, with records kept; the extended 5–7 year warranties premium brands such as Daikin and Mitsubishi Electric offer through accredited installers carry the same condition. Miss a year and a later failure may be refused — see warranty and servicing requirements, and what a service includes.
Frequently asked questions
Get your servicing on a schedule
Tell us about your system — home or commercial, how many units — and we match you with vetted, F-Gas certified engineers who quote for one-off visits or a planned schedule. Free, no obligation.