When choosing an AC you'll encounter two main variants: single-split(one indoor unit on one outdoor unit) and multi-split (multiple indoor units on one outdoor unit). This article explains the difference, costs, and which variant fits your home best.
What is a single-split AC?
A single-split consists of exactly two parts: one outdoor unit (the compressor) and one indoor unit (the blower). They're connected by one set of refrigerant lines. Ideal for one room such as the living room, bedroom or home office.
What is a multi-split AC?
A multi-split also has one outdoor unit but connects to 2 to 5 indoor units. Each indoor unit has its own piping and remote, so you control every room independently. Ideal for homes where multiple rooms need cooling or heating.
The main differences
| Property | Single-split | Multi-split |
|---|---|---|
| Number of rooms | 1 | 2 – 5 |
| Number of outdoor units | 1 | 1 |
| Purchase price | from €1,699 | from €3,200 |
| Installation time | 4–5 hours | 1–2 days |
| Annual maintenance | €200 | €270 – €480 |
| Per-room control | Yes (one room) | Yes (each room separately) |
| Number of wall passages | 1 per outer wall | One per indoor unit |
When to choose single-split?
Single-split is the right choice if:
- You only want to cool or heat one room.
- Your living room is the "hangout" — one AC is often enough.
- Rooms are far apart — long piping reduces efficiency.
- You want maximum capacity in one space (e.g. a large conservatory).
- Your budget is limited.
When to choose multi-split?
Multi-split is advantageous if:
- You want to cool or heat 2 or more rooms.
- You want only one outdoor unit (aesthetics or HOA requirements).
- The rooms are relatively close together.
- Your HOA or municipality limits the number of outdoor units.
- You want to control each room independently.
Tip: from 3 indoor units onwards, multi-split is typically cheaper than separate single-splits — thanks to fewer outdoor units, fewer wall passages and a shared electrical circuit.
Example: 3 rooms
Suppose you want to cool three rooms: living room and two bedrooms. Which is cheaper?
| Solution | Purchase | Maintenance/year | Outdoor units |
|---|---|---|---|
| 3× single-split | ~€5,097 | 3× €200 = €600 | 3 |
| 1× multi-split (3 indoor units) | €4,200 | €340 | 1 |
Multi-split is €897 cheaper to buy in this example and €260 cheaper per year in maintenance. Plus: one outdoor unit looks tidier on your facade.
Important points
Outdoor unit capacity
With multi-split the outdoor unit shares its capacity across active indoor units. If all indoor units run simultaneously, maximum capacity per room can be lower than with single-split. We calculate this precisely in the quote.
Future expansion
Want to add a room later? Only possible if your outdoor unit still has spare capacity. We advise reserving headroom at installation — for example by choosing a unit capable of 4 indoor units while you install 3 now.
Aesthetics and HOA
HOAs often impose strict rules on the number of outdoor units. With multi-split you have only one — usually making HOA approval easier. Read more in our guide on AC in an apartment.
Conclusion
The choice between single-split and multi-split mainly depends on how many rooms you want to serve. For one room, single-split is by far the cheapest. From 2–3 rooms, multi-split becomes more attractive — in cost, maintenance and aesthetics.
Read more on our pages about AC installation and multi-split systems. Or request a free quote directly.