Multi-split systems

A multi-split cools and heats several rooms from a single outdoor condenser, with a separate indoor unit in each room. It is the tidy answer to whole-home comfort: instead of a row of outdoor units, you have one, and each room still gets its own temperature and controls. Most residential systems run two to five indoor units on one outdoor unit, some up to six.

The real flexibility is that you can mix indoor formats on the same system: a discreet wall unit in a bedroom, a floor console under a window, a ceiling cassette in an open-plan kitchen. Current UK ranges from Daikin, Mitsubishi Electric, Fujitsu, LG and Samsung all use R32 and are reverse-cycle, so they heat as well as cool.

Sizing and diversity. Each room is heat-load sized for its own indoor unit, then the outdoor unit is chosen using diversity: below the sum of the indoor capacities, on the basis that not every room runs flat out at once. This keeps the outdoor unit compact and quiet. Oversizing the whole system is a common and costly mistake, so a good design meets your peak demand while spending most of its life modulating gently.

Install and cost. Every indoor unit needs its own refrigerant pipe run back to the single outdoor location, so pipework and route planning are a bigger part of the job than a single split, and cost scales with the number of heads. As a guide, budget roughly £2,800 to £4,500 for two rooms and £3,500 to £7,000 for three to four, supplied and fitted, with each extra head adding around £700 to £1,500. These are secondary-sourced bands, so get two or three installer quotes.

Multi-split, single splits or ducted. Choose a multi-split for two or more rooms where outdoor space is limited. Separate single splits can cost less per room and isolate faults. Ducted hides everything for the tidiest finish but costs the most and suits a renovation or new build.

Prices and running costs correct as of July 2026. The energy price cap changes quarterly, so check current rates before budgeting.