Make your garden office usable in a heatwave and through the winter, with one small split system.
Free, no obligation
Standard or pre-charged systems
A garden room is one of the best places for air conditioning: it is a single, well-defined room that overheats in summer and gets cold in winter. A small split system, often around 2.5 kW, cools and heats it. A pre-charged system often suits, provided the outdoor unit sits close by and an electrician confirms the supply.
Home officesSmall rooms with screens and big windows overheat quickly in summer.
Year-round useThe same unit heats in winter, so the room is comfortable in every season.
Studios and gymsSteady temperature for equipment, instruments and exercise.
Annexes and summer housesGuest rooms and garden annexes, cooled and heated.
Garden rooms with lots of glazing need more cooling for their size than a house room.
Free sizing toolTakes 10 secondsA single garden room is often a good fit for a pre-charged system, as long as the outdoor unit can sit close by.
| Standard installed | Pre-charged | |
|---|---|---|
| F-Gas engineer needed | Yes | No, for a typical install |
| Electrician needed | Yes | Yes |
| Rooms per outdoor unit | One or several | One |
| Pipe run | Longer runs possible | Limited to the supplied kit unless a technician extends it |
| Indoor unit styles | Wall, floor, cassette, ducted | Mostly wall-mounted |
| Cooling and heating | Yes | Yes |
| Best for | Whole homes, larger rooms, businesses | One room where the outdoor unit can sit close by |
Home or business, how many rooms and the system type you would like.
Only installers who cover your postcode and fit your system type.
Weigh up prices, equipment and warranties, then choose, if you want to.
An air conditioner with an indoor unit in the room and an outdoor unit outside, joined by refrigerant pipes and a cable.
Units of cooling or heating output. 1 kW is about 3,412 BTU per hour. Units are sold in sizes such as 2.5 kW (9,000 BTU) and 3.5 kW (12,000 BTU).
A compressor that speeds up and slows down to hold the temperature, rather than switching fully on and off. Quieter and more efficient.
Seasonal efficiency ratings for cooling (SEER) and heating (SCOP). Higher numbers mean less electricity for the same comfort.
The qualification needed to install and work on equipment containing fluorinated refrigerants, which most standard systems use.
A split system sealed at the factory with a non-fluorinated refrigerant and a pre-flared pipe kit, so a typical install needs no F-Gas engineer.
One outdoor unit serving two or more indoor units in different rooms.
Water removed from the air while cooling, carried outside by a drain pipe or pump.
Another name for a reversible air conditioner: it moves heat from outside air into the room in winter.
Many garden rooms use about 2.5 kW, and larger or very glazed rooms about 3.5 kW. Use the size guide on this page, and an installer will confirm.
Often yes, because it is one room and the outdoor unit can usually sit close by. It still needs a qualified electrician.
It needs a supply with enough capacity, usually from the house by armoured cable, and the air conditioner on its own circuit. An electrician will check.
Yes. Split air conditioners heat as well as cool.
Garden rooms and outdoor units each have their own rules on size and position, and listed buildings and conservation areas have extra controls. Check with your council or installer.
Enter your postcode, tell us about the garden room and compare quotes from local installers.
General information only, not technical, legal or planning advice. Installers confirm system size, siting and any permissions for your property. Updated October 2026.
Sources: The Fluorinated Greenhouse Gases Regulations (GB) and GOV.UK guidance on F-gas; Approved Document P (electrical safety) and the Building Regulations for England and Wales; the Energy Performance of Buildings Regulations (air conditioning inspections); manufacturer installation guidance for split systems.