The three systems
Once you want more than two rooms cooled, the question becomes how to serve them. The choice affects what you see on the walls inside and out, and how much building work is involved.
A unit pair per room
Suits: adding rooms one at a time
- Rooms are fully independent
- Simple to extend later
- Several boxes on the outside walls
- Harder to place in tight gardens
Multi-split
Suits: three to five rooms with limited outside space
- One outdoor unit serves every room
- Separate temperature in each room
- Room count is fixed when it’s sized
- Some long pipe runs inside the house
Concealed ducted
Suits: full renovations and loft-space homes
- No wall units, just discreet grilles
- Quiet, even airflow
- Needs ceiling or loft space for ducts
- Best done while ceilings are open
Compared
Scroll sideways to compare all three
| Point | Unit pair per room | Multi-split | Ducted |
|---|---|---|---|
| Outside the house | One unit per room | One unit in total | Usually one unit |
| Inside each room | Wall unit | Wall, floor or cassette unit | Ceiling or wall grille |
| Temperature control | Every room | Every room | Per zone |
| Building work | Minimal | Light | Significant in a lived-in home |
| Growing later | Straightforward | Up to the outdoor unit’s limit | Hard |
Which suits your house
The housing around Guildford is mixed, and that usually points towards one answer.
- 1930s semis in Burpham, Merrow and Stoughton. A multi-split is the common choice. The outdoor unit sits at the side or rear, with short pipe runs up to the bedrooms.
- Victorian terraces near the centre. With little outside wall to spare, a multi-split with one compact outdoor unit at the back keeps the street frontage clear.
- Larger detached homes towards Shalford, Clandon and the Horsleys. Ducted works well when the loft is boarded or a renovation is planned. Otherwise a multi-split serves the bedrooms.
- New homes in Woking and on Guildford’s edge. These often have the loft space and modern wiring to make ducted practical.
Mixing systems is fine
Many whole-house jobs combine approaches, such as ducted on the top floor and a wall unit in the kitchen extension. The survey sets out what fits where.
Phasing the work
You don’t need to do every room at once. These steps keep later rooms simple:
- Tell the surveyor your full planEven if you only fit two rooms now, the outdoor unit can be sized for more.
- Run spare pipe routes during building workIf walls or ceilings are open for other reasons, pipes for future rooms cost far less to lay now.
- Add rooms when it suits youEach later room is a shorter, cheaper visit.
Start with the rooms you know about
List them in the estimate and mention the rest at the survey.