What is a split system?
A standard split system consists of one outdoor unit connected to one indoor unit. The indoor unit is typically wall-mounted, and the two are linked by refrigerant pipework running through a small hole in the wall. Split systems are the most common type of air conditioning installed in UK homes and offices — they are cost-effective, efficient and relatively straightforward to install.
What is a multi-split system?
A multi-split system connects a single outdoor unit to two or more indoor units, each serving a different room. The outdoor unit is larger and more powerful, but you avoid having multiple outdoor units cluttering the exterior of the building. Each indoor unit has its own controls and can typically be set to a different temperature independently.
Key differences at a glance
| Feature | Single split | Multi-split |
|---|---|---|
| Rooms served | 1 | 2–8 |
| Outdoor units | 1 per room | 1 shared unit |
| Installation cost | Lower per unit | Higher upfront, better value at 3+ rooms |
| Independent zone control | Yes (by default) | Yes |
| Flexibility to add rooms | Add another unit later | Limited by outdoor unit capacity |
When to choose a single split system
If you only need air conditioning in one room — a home office, bedroom or conservatory — a single split system is almost always the better choice. It costs less to install, is simpler to maintain and gives you the option to add further units later if you decide you want cooling in other rooms.
When to choose a multi-split system
Multi-split systems make most sense when you need cooling or heating in three or more rooms and want to avoid a row of outdoor units on your property. They are also the preferred option where a homeowners' association or planning authority restricts the number of external units that can be installed.
Get free quotes for either system
A qualified F-Gas engineer can survey your property and recommend the right system for your needs and budget. Use our free quote service to get up to 3 competitive quotes from vetted local air conditioning engineers.