How each system works
A split system has one outdoor compressor connected by copper pipes to one indoor head mounted on a wall. Each room you want conditioned needs its own indoor head (and either its own compressor — a single split — or a shared compressor — a multi-split). A ducted system has one large outdoor compressor connected to a single indoor air handler in the roof cavity. The air handler pushes conditioned air through insulated ducts to vents in every room, with zone controllers letting you turn rooms on or off.
| Factor | Split system | Ducted |
|---|---|---|
| Typical installed cost | $1,800–$8,000 (1–3 rooms) | $9,000–$22,000 (whole home) |
| Install time | 3–5 hours per room | 2–3 days |
| Cools whole home | No — room by room | Yes — with zoning |
| Running cost (couple, 2 rooms used) | Lower | Higher |
| Running cost (family, whole house) | Higher | Lower with zoning |
| Aesthetics | Wall units visible | Slim ceiling vents only |
| Adds resale value | Modest | Significant (mid-premium homes) |
| Best for | Apartments, 1–3 rooms, tight budget | 4+ rooms, owner-occupiers, roof cavity available |
Cost comparison
Single split: $1,800–$3,500 per room. Multi-split (3 rooms from one outdoor unit): $5,000–$8,000. Fully ducted (3–4 bedroom home): $9,000–$16,000. If you need 4+ rooms conditioned, ducted starts to win on price per room. If you only need 1–2 rooms, split systems are dramatically cheaper.
Running cost comparison
Per kWh of cooling, both modern inverter systems are similar in efficiency. The difference is what you USE: a ducted system tempts you to cool the whole house all day. A split system makes you cool only the room you're in. For a couple in a 4 bedroom home who only use 2 rooms, splits are 40–60% cheaper to run. For a family who genuinely uses every room, ducted with zoning is similar or slightly cheaper to run.
Install complexity
Splits install in 3–5 hours per room with minimal disruption. Ducted needs roof cavity access, ceiling penetrations for vents in every room, electrical upgrades, and 2–3 days of work. Older homes with low roof cavities, exposed beams or asbestos issues can struggle to fit ducted economically.
Aesthetics
Ducted is almost invisible — just slim ceiling vents. Splits put a 90–110 cm white wall unit in every conditioned room. For style-conscious buyers, ducted wins unless cassette splits or discreet bulkhead splits are used (more expensive).
Resale value
Real estate agents consistently report that ducted reverse-cycle adds more perceived value to a home than several splits — particularly in mid-to-premium markets. For investment properties, a couple of splits delivers more rental yield per dollar invested.
When to choose which
Choose splits if: you have 1–3 rooms to cool, your budget is under $8,000, your home doesn't have roof cavity, or you're in a unit/apartment. Choose ducted if: you want whole-home cooling, your budget allows $9,000+, you have good roof cavity, and you'd genuinely use 4+ rooms simultaneously. A hybrid approach (ducted for living/bedrooms + a separate cassette split for a granny flat or home office) is increasingly popular.