Most homeowners in Australia narrow their aircon choice down to two options: ducted reverse cycle, or a set of multi-split units. The decision is bigger than people think — it affects installation cost, ceiling design, future renovation flexibility, and how the home actually feels to live in for the next decade.
Neither option is automatically better. They suit different homes for different reasons.
What ducted aircon actually is
Ducted reverse cycle uses a single outdoor compressor connected to one or two indoor units hidden in the ceiling cavity. Air gets distributed through ductwork to multiple rooms via vents in the ceiling.
Modern systems are zoned — meaning you can shut off airflow to rooms you are not using and concentrate cooling or heating where you actually need it. Properly zoned, a ducted system can match the running cost of a multi-split despite being a larger unit.
Visually, the only thing you see in each room is a ceiling vent. No wall-mounted heads, no visible cables, nothing breaking up the room aesthetic.
What multi-split aircon actually is
A multi-split system uses one outdoor compressor connected to several indoor wall-mounted heads (typically 2 to 5). Each indoor head serves one room and operates independently — different temperatures, different on/off schedules.
You can run only one head, or all of them, or anywhere in between. The system scales its energy use to match.
Visually, you have a wall-mounted unit in each room being cooled. They are smaller than they used to be — modern designs are slim and white — but they are still a visible piece of equipment on the wall.
Cost comparison — installed in 2026
For a typical 4-bedroom Australian home:
- Multi-split (4 indoor heads): $9,000 to $15,000 supplied and installed
- Ducted reverse cycle (zoned, 4-6 zones): $14,000 to $22,000 supplied and installed
Ducted is roughly 50-60% more expensive upfront. The cost gap closes when you factor in long-term running costs in a properly zoned system, but the headline difference is real.
Where ducted wins
- Aesthetic: Nothing on the walls. Ceilings show only vents. Best for design-conscious homes or open-plan living areas.
- Quietness: The compressor is outside, the indoor unit is in the ceiling cavity. Living spaces hear almost nothing.
- Whole-house comfort: Even temperatures across the home, no transition zones between cool rooms and hot hallways.
- Resale value: Ducted is the default expectation in homes priced above the median. Multi-split can be a flag in real estate listings for higher-end properties.
Where multi-split wins
- Lower upfront cost: 30-40% cheaper to install on a comparable home.
- Renovation simpler: If you only need cooling in 2-3 rooms today, you can install a 2-head system and add more later.
- Fits homes ducted cannot: Low ceiling cavities, complex roof structures, or two-storey homes with limited cavity space often rule out ducted.
- Failure isolation: If an indoor unit fails, only that room loses cooling. A ducted system failure takes the whole house out at once.
- Independent room control: Useful for households where people want different temperatures in different rooms (kids’ rooms cooler at night, master warmer in winter).
Common mistakes in choosing
Picking ducted because “it’s the better option”
It is not automatically better. A ducted system in an unzoned configuration runs the whole house all the time and costs more to operate than 2-3 multi-split heads serving the rooms actually being used. The “better” depends entirely on usage pattern.
Picking multi-split for a 5-bedroom home
Beyond 4 indoor heads, you start running into compressor capacity limits and complex line set runs. By the time you have 5+ rooms requiring cooling, ducted often becomes the practical choice — both technically and economically.
Underestimating the install complexity of ducted
Ducted needs at least 350-500mm of clear ceiling cavity space, multiple roof penetrations, and a return air pathway. Older homes with shallow roof spaces, complex hip rooflines, or no return air provisioning end up with ugly bulkheads dropping ceilings to fit ductwork.
A simple decision framework
Pick ducted if:
- You want a whole-home cooling experience with no visual equipment in rooms
- The home has 350mm+ of clear ceiling cavity space
- Budget allows for the higher upfront cost
- You will use zoning properly (set zones for actual use patterns, not run the whole system always)
Pick multi-split if:
- You only need cooling in a few specific rooms
- Budget is the primary constraint
- The roof cavity rules out ducted (low ceilings, complex roof, two-storey limitations)
- You want the option to add more rooms later without major rework
- Different household members want different temperatures simultaneously
Either way, get the design conversation done before you commit to a system. The wrong choice for the home is the most expensive aircon decision homeowners make — and it shows up in comfort, bills, and resale value for years afterwards.
