Guides
Costs, system choices, sizing and the rules that apply to commercial air conditioning in the UK.
Guides
Plain-English guides to costs, system choices, sizing and the rules that apply to commercial air conditioning in the UK. Each one starts with a short answer, then the detail.
Commercial air conditioning costs in 2026
Commercial air conditioning in the UK typically costs £1,450–£2,950 plus VAT for a single wall-mounted split, £2,150–£4,950 per ceiling cassette, and £2,450–£4,950 per indoor unit on a VRF system. Servicing starts at around £175–£245 for a visit covering the first indoor unit. Location, access, pipe lengths and electrics move the price most.
Choosing a commercial air conditioning system
Choose a wall-mounted split for one or two small rooms, ceiling cassettes for open spaces with a suspended ceiling, ducted units where appearance matters, and VRF once you need more than about six to eight indoor units or central control. The heat load, ceiling, outdoor space and budget decide the rest.
Sizing air conditioning for an office
As a rough guide, offices need about 80–125 W of cooling per square metre, so a 50 m² office might need about 4–6 kW. Dense occupancy, lots of IT, large south- or west-facing windows and top-floor rooms push the figure up. A heat load calculation per zone gives the real answer.
F-gas rules for businesses
If your air conditioning holds 5 tonnes CO2 equivalent of F-gas refrigerant or more, you — as the operator — must have it leak-checked by a certified engineer at least every 12 months (6 months from 50 tonnes, 3 months from 500 tonnes), repair leaks promptly and keep records for at least five years.
TM44 inspections explained
In England, Wales and Northern Ireland, if the air conditioning you control in a building adds up to more than 12 kW of effective rated output, it needs an energy inspection by an accredited assessor at least every five years. In Scotland, systems of 12 kW or more need inspecting by an accredited expert, at intervals the expert sets. Not having a valid report can lead to a £300 penalty in England and Wales and in Northern Ireland.
Replacing R22 and R410A systems
R22 systems can still run, but they cannot be topped up with R22, so most refrigerant-circuit repairs are no longer possible — replacement is usually the realistic option when they fail. R410A systems can be serviced and repaired as normal; plan replacement when they become unreliable or costly to run, not because of a ban.
How often to service commercial air conditioning
Service commercial air conditioning at least once a year, and every three to six months in kitchens, gyms, salons, dusty sites and server rooms that run 24/7. Systems at or above 5 tonnes CO2e also need F-gas leak checks at the legal frequency, which can be done on the same visit.
Air-to-air heat pumps for business heating
Yes. Reverse-cycle air conditioning is an air-to-air heat pump and can be the main heating for many offices, shops and studios, delivering several units of heat for each unit of electricity. It needs sizing for winter heating output, sensible controls and outdoor units positioned for defrost drainage.
Server room cooling guide
Cool a server room with dedicated units sized to the IT load in kW plus a margin for growth, usually as a duty/standby (N+1) pair with automatic changeover, low-ambient controls for winter, and a temperature alarm. ASHRAE recommends equipment inlet air of about 18–27°C.
Planning permission and landlord consent for air conditioning
Outdoor air conditioning units on commercial buildings often need planning permission — especially on front or visible elevations, in conservation areas and on listed buildings — and councils may ask for a noise assessment. Leased premises almost always need the landlord's written consent for external units and wall penetrations.
Ventilation vs air conditioning
Air conditioning heats and cools the air already in a room; ventilation replaces it with fresh outdoor air. Most occupied commercial spaces need ventilation to control CO2 and odours, and air conditioning where they overheat — ideally designed together, often with heat recovery.
Choosing an air conditioning contractor
Check F-gas company and engineer certification, get a written specification with the make, model, capacity, refrigerant and everything included, confirm who handles electrics, condensate, access and paperwork, and agree servicing so the manufacturer warranty stays valid.
Reducing air conditioning running costs
The biggest savings usually come from sensible set points (around 24°C cooling, 20°C heating with a dead band between them), time schedules, clean filters and coils, closing doors or fitting air curtains, shading glazing, and replacing old fixed-speed equipment with modern inverter systems.