Air conditioning for garden rooms and garden offices
A garden office can be the best room you own in spring and the worst one in July. We fit small, quiet wall units in garden offices, studios and gyms across London and the Home Counties, for cooling in summer and efficient heating in winter, with a fixed price including VAT.
- 2.5 kW wall unit, inc. VAT, from
- £1,850
- most single rooms fitted
- In a day
- warm in winter, cool in summer
- Heats too
- workmanship guarantee
- 2-year
Why garden rooms overheat
Garden rooms are small, often heavily glazed and usually sit in full sun. A lightweight timber or composite structure warms up quickly, and a laptop, a screen and a person add more heat in a small space. By mid afternoon in summer, many are too hot to work in.
In winter the problem flips. A plug-in heater warms the room slowly and costs a lot to run. A wall-mounted air conditioner is a heat pump, so the same unit cools in summer and heats in winter, using less electricity than a direct electric heater for the same warmth.
Insulation comes first
Air conditioning works best in a room that holds its temperature. A well-insulated garden room with double glazing needs only a small unit. A thin, uninsulated summerhouse needs more capacity, costs more to run and may never feel quite right.
At the survey we ask what's in the walls, floor and roof, and look at the glazing and which way it faces. Blinds or solar film on big south or west-facing windows can make a real difference. If the building is badly insulated, we'll tell you before you spend money on a bigger unit.
Typical unit sizes for garden rooms
A guide only. Your survey confirms the right size.
| Garden room | Typical use | Starting point |
|---|---|---|
| Small office, up to about 10 m², well insulated | One person working | 2.5 kW wall unit, from £1,850 inc. VAT |
| Larger room or studio, very glazed or used by two | Studio, two desks or a hobby room | 3.5 kW wall unit, from £2,050 inc. VAT |
| Home gym | Exercise raises the heat load quickly | Often one size up from the floor area alone |
Our guide to sizing explains how floor area, glazing and use change the answer.
Power to the garden room
Air conditioning needs a proper electrical supply. Many garden rooms are fed by an armoured cable from the house, but some only have a light circuit or an extension lead. The supply must be sized for everything in the room, including the air conditioner.
In England, adding a new circuit is notifiable work under Part P of the Building Regulations. It must be done by an electrician registered with a competent person scheme, or approved by building control. We check the existing supply at the survey and tell you if it needs upgrading first.
Small units and short pipe runs
A garden room is often an easy install. The outdoor unit usually sits on a bracket or a ground stand on the back or side wall of the garden room itself, close to the indoor unit, so the pipe run is short. The indoor unit goes high on a wall where it can blow along the room, not straight at your desk.
We check the wall can take the fixings. Some garden room walls are thin panels that need a stand on the ground for the outdoor unit instead of a wall bracket.
Planning rules for the outdoor unit
A heating-capable air conditioner counts as an air source heat pump under Class G, which covers units on a house or on a building within its grounds, such as a garden room. Each rule must be met.
- The unit must heat as well as cool. A cooling-only unit needs planning permission
- It counts towards the limit: one heat pump in total for a terraced or semi-detached house and its garden, or two for a detached house
- The outdoor unit must be no bigger than 1.5 m³
- Not on a pitched roof, and on a flat roof at least 1 metre from the edge
- It must pass the MCS 020(a) noise calculation: no more than 37 dB(A) outside a neighbour's habitable room window or door
- In a conservation area, not on a wall or roof facing a highway, and no nearer a bordering highway than the house
- If the house is listed, a unit anywhere in its grounds needs planning permission
- Sited to keep its effect on the look of the area to a minimum, and removed when no longer needed
The garden room itself
Most garden rooms are built as permitted development outbuildings. The main limits: single storey, no more than 2.5 m high within 2 m of a boundary, no further forward than the front of the house, and no more than half the garden covered by buildings. They must be used for something incidental to the house, such as a home office or gym, not as a separate home.
Under Building Regulations, a detached outbuilding under 15 m² with no sleeping accommodation is usually exempt. Between 15 and 30 m² it's usually exempt too, if there's no sleeping accommodation and it's at least 1 m from the boundary or built mainly of non-combustible materials. If the house is listed or in a conservation area, ask the council first.
Garden room air conditioning prices
Home prices including VAT. If the garden room needs a new electrical supply, that's priced separately.
- from£1,850inc. VAT
A bedroom or study
2.5 kW wall unit, 5 m pipe, fitted in a day
- from£2,050inc. VAT
A living room
3.5 kW wall unit
- from£250inc. VAT
Premium range upgrade
Quieter, more efficient unit
Garden room air conditioning questions
Can you put air conditioning in a garden office?
Yes. A small wall-mounted split system suits most garden offices. The outdoor unit usually goes on the garden room wall or a ground stand beside it, so the pipe run is short and the install is straightforward.
Do I need planning permission for air conditioning on a garden room?
Often not. Class G covers a heating-capable unit on a building within the grounds of a house, if every rule is met. It counts towards the house's limit of one heat pump, or two on a detached house. Listed buildings need permission.
What size air conditioner does a garden room need?
A small, well-insulated garden office usually suits a 2.5 kW unit. Larger, very glazed rooms or home gyms often need 3.5 kW. We confirm the size at the survey after checking insulation, glazing and use.
Does my garden room have enough power for air conditioning?
It depends on the existing supply. A garden room fed by a proper armoured cable and its own circuit may be fine. A new circuit is notifiable under Part P, so it must be done by a registered electrician or signed off by building control.
How much does garden room air conditioning cost?
A 2.5 kW wall unit starts from £1,850 inc. VAT, and a 3.5 kW unit from £2,050 inc. VAT. Any upgrade to the electrical supply is priced separately after the survey.