Multi-split air conditioning: one outdoor unit, several rooms
By Dale @ ukaircontracker · facts checked
Quick answer
A multi-split air conditioner connects two to five indoor units to a single outdoor unit, so you can cool or heat several rooms without a row of condensers on the wall. In the UK a 2–3 room multi-split system typically costs £3,000–£5,500 installed. Each room has its own controls, but every indoor unit shares one compressor.
| Feature | Multi-split | Separate single splits |
|---|---|---|
| Outdoor units | One | One per room |
| Typical cost, 2–3 rooms | £3,000 – £5,500 | £1,500 – £2,500 per room |
| If the outdoor unit fails | Every room loses cooling | Only one room is affected |
| Best for | Limited wall space outside, flats, terraces | Rooms far apart, or adding rooms over time |
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How it works
Each indoor unit has its own refrigerant pipe pair running back to the shared outdoor unit. The outdoor unit is sized for the rooms connected to it, so you choose the system for the number of rooms you want from the start. Adding a room later is only possible if the outdoor unit has a spare port and enough capacity.
Most multi-split systems let each room be set to its own temperature. Mixing heating in one room and cooling in another at the same moment is not normally possible on a standard multi-split.
When to choose it
A multi-split makes sense when there is only one sensible place for an outdoor unit, or when you want two or three bedrooms done in one job. If the rooms are on opposite sides of the house, the long pipe runs can cost more than fitting two single splits.
Look at the kit — then buy it
MeacoCool MC Series Pro 9,000 BTU
Pro Breeze 12,000 BTU 4-in-1 Smart AC
AuraHome Portable AC 9,000 BTU — 4-in-1 Cool/Dehumidify/Fan
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Common questions
- How many rooms can a multi-split system run?
- Domestic multi-split outdoor units typically run two to five indoor units. The exact number depends on the model and the size of each room.
- Is a multi-split cheaper than separate split systems?
- For two or three rooms close together it is often similar or cheaper, and it needs only one outdoor unit. For rooms far apart, separate single splits can work out cheaper because the pipe runs are shorter.
- Can each room have a different temperature?
- Yes. Each indoor unit has its own controller and thermostat. On a standard multi-split all rooms must be in the same mode, heating or cooling, at the same time.