Short answer
Neither is better in the abstract. Split systems suit cooling one or two rooms, cost far less to install and can be added over time. Ducted suits whole-home cooling, leaves no indoor units on any wall, and with zoning lets you cool only the parts of the house in use. The deciding factors are usually how many rooms you actually need to cool, whether your roof space can take ducting, and your budget.
How each one works
A split system has an indoor head on the wall connected to an outdoor condenser by refrigerant pipework. One head serves one space. A multi-split runs several heads from a single outdoor unit.
Ducted places a fan coil in the roof space and distributes air through ducting to outlets in each room, with a single outdoor condenser and a wall controller.
When a split system is the better answer
Splits tend to win when:
- Only one or two rooms genuinely need cooling
- The budget rules ducted out for now
- There is no usable roof space, or access is too tight
- You want to add cooling gradually, room by room
- Rooms are used independently and rarely at the same time
- The property is a unit or apartment
When ducted is the better answer
Ducted tends to win when:
- Most of the house needs cooling
- You do not want indoor units visible in living areas or bedrooms
- The home is being built or substantially renovated
- Several splits would otherwise be needed, along with several outdoor units
- Different parts of the house are used at different times, so zoning will pay off
- There is adequate roof space, height and access
Running costs
This is where the comparison is often oversimplified. An unzoned ducted system cooling the whole house to cool one room is expensive. A well-zoned ducted system cooling only the occupied zones can be very reasonable.
Splits are efficient at cooling exactly the room they serve, but running four splits at once is not automatically cheaper than one properly zoned ducted system.
The honest answer is that it depends on your house, your zoning and how you actually use the space. Anyone quoting you a specific percentage saving without seeing the property is guessing.
What decides it in a Brisbane home
Roof space is the first practical gate. Many older Brisbane homes, particularly high-set timber houses with shallow roof pitch, simply do not have the room or access ducted needs.
After that it is room count and budget. There is no shame in starting with a split in the main living area and adding more later; it is a common and sensible path.
General comparison only. The right system for your property depends on an assessment of the rooms, the building and how you use it.