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Buying guide · 4 minute read
Single split or multi split: which is right for you?
Both heat and cool your home or business. The difference is how many rooms one outdoor unit looks after. Here's how each works, what it costs and how to choose.
The quick answer
Which one do you need?
- SingleOne room or area, like a bedroom, home office, conservatory, server room or small shop.
- MultiTwo to five rooms with space for only one outdoor unit, like several bedrooms or office rooms.
- Single ×2Two rooms with space for two outdoor units. Simple, and each room keeps working if the other has a fault.
Single split
What is a single split system?
A single split is one outdoor unit connected to one indoor unit. It's the most popular type of air conditioning in UK homes and small businesses. The indoor unit sits high on the wall of one room, and the outdoor unit sits outside on a bracket or ground stand.
How it works
Two small copper refrigerant pipes, a power and control cable and a drain pipe join the units through one neat 65mm hole. In summer the system takes heat out of the room and releases it outside. In winter it runs in reverse as a heat pump, taking heat from the outside air and moving it indoors, even when it's below freezing.
Multi split
What is a multi split system?
A multi split is one larger outdoor unit connected to two or more indoor units, usually up to five depending on the outdoor unit. Each room gets its own indoor unit with its own remote or app control, but they all share one outdoor unit.
How it works
Each indoor unit has its own pipe run back to the outdoor unit, so every room can be set to its own temperature and switched on or off on its own. The outdoor unit adjusts its output to match the rooms that are running. One thing to know: all rooms run in the same mode at once. They all heat or all cool, so one room can't heat while another cools.
Side by side
Single split vs multi split
The key differences at a glance.
| Feature | Single split | Multi split |
|---|---|---|
| Rooms or areas | 1 | 2 to 5 |
| Outdoor units | 1 per room | 1 for all rooms |
| Fitted price at Airomax | From £2,000 | From £3,800 for 2 rooms |
| Temperature control | Fully independent | Independent, but all rooms heat or all cool |
| If the outdoor unit has a fault | Only that room is affected | Every connected room stops |
| Efficiency | Best for a single room | Best when several rooms run together |
| Install time | Usually 1 day | Usually 1 to 2 days |
| Best for | Bedrooms, home offices, conservatories, server rooms, single shops | Several bedrooms, whole floors, offices with several rooms |
Pros and cons
The good and the not so good
Single split
- Lowest price for one room
- Most efficient for that room
- Each room is independent, so a fault never affects another
- Quickest to install
- Each room needs its own outdoor unit
Multi split
- One outdoor unit for up to five rooms
- Tidier outside, ideal for small gardens, terraces and shopfronts
- Often the best value for three or more rooms
- All rooms heat or all cool at the same time
- A fault outside affects every room
- Adding rooms later needs a spare connection
Homes and businesses
Which should you choose?
Find the situation closest to yours.
I want to cool a bedroom, home office or conservatory.
Single splitI want three or more bedrooms comfortable in summer.
Multi splitI only have space for one outdoor unit, like a small yard or one wall.
Multi splitI want two rooms and there's space outside for two units.
2 single splitsI want to heat one room while cooling another.
Single splitsMy business has a server or comms room that must never stop.
Single splitMy office has several small rooms or meeting rooms.
Multi splitI might add more rooms in the future.
Multi split with a spare port
For businesses
Air conditioning for offices, shops and salons
The same choice applies at work. A single split suits one office, a shop floor or a server room. A multi split suits several small offices or meeting rooms where outside space is limited. For larger open-plan areas, a ceiling cassette or ducted system spreads air more evenly.
- Free site survey and a fixed written price
- Out-of-hours installation, so you don't lose trading time
- F-Gas certificates and records for your compliance file
- Servicing and repairs to keep systems running
Prices
How much do they cost?
Fixed, fully fitted prices, including the units, installation, up to 15m of pipework and commissioning.
Prices from our current range, October 2026. Larger rooms need bigger units. 0% finance is available on selected systems, subject to status.
How we install
How Airomax installs your system
Single or multi split, our F-Gas certified engineers handle the whole job from first price to final paperwork.
Get your fixed price
Answer a few questions online and see your installed price straight away. For larger homes and businesses we offer a free survey.
We plan the job
We agree where each indoor and outdoor unit goes and the neatest pipe route, then book a date that suits you, including evenings and weekends for businesses.
Installation day
We fit the indoor units, drill one 65mm hole per room, mount the outdoor unit and run the pipework in tidy white trunking.
Testing and commissioning
Pipework is pressure-tested and vacuumed before the refrigerant is released. Then we test every room on heating and cooling.
Handover
We set up the app on your phone, show you how everything works and leave your home or premises tidy.
Paperwork
You get your F-Gas compliance certificate and your warranty details.
Why Airomax
Installed properly, first time.
F-Gas certified engineers
Safe, compliant installation for homes and businesses across the UK.
About usFixed prices
See your fully installed price online. No surprises, and 0% finance on selected systems.
FinanceFast installation
Most homes are done in a day. Evening and weekend installs for businesses.
Installation processFAQs
Your questions answered
Still unsure? Call us on 0330 043 7869, 7 days a week.
Is a multi split cheaper than two single splits?
For two rooms the price is usually similar. Our Daikin multi split for two rooms is £3,800 fitted, compared with £4,000 for two Daikin single splits. For three or more rooms a multi split usually costs less and needs only one outdoor unit.
Can I add another room to a multi split later?
Only if the outdoor unit has a spare connection and enough capacity. If you think you'll add a room later, tell us when you get your quote and we'll fit an outdoor unit that leaves room to grow.
Can one room heat while another cools on a multi split?
No. On most multi split systems every indoor unit runs in the same mode, heating or cooling, at the same time. Each room can still have its own temperature and fan speed, and any room can be switched off.
Which is more energy efficient?
A single split is matched exactly to one room, so it's usually the most efficient choice for that room. A multi split is efficient when several rooms are used together. The systems we install are A++ rated or better.
Which is best for an office or shop?
For one open-plan office or shop floor, a single split, or a ceiling cassette for larger spaces, is usually best. For several small offices or meeting rooms, a multi split runs them all from one outdoor unit. Server rooms should always have their own single split.
How long does installation take?
A single split is usually installed in one day. A multi split for two to four rooms usually takes one to two days. For businesses we can install out of hours so you don't lose a day's trading.
Do I need planning permission?
Many homes don't, but it depends on where the outdoor unit goes and on your property. Listed buildings, conservation areas, flats and commercial premises can have extra rules. We check this with you before installation.
Get your fixed price in under a minute
Prefer to talk? Call 0330 043 7869, 7 days a week.