Two systems dominate Sydney homes: split systems and ducted. Both cool and heat well — the right choice comes down to how many rooms you want to control, your budget, and whether you're renovating.

Split systems

A split system has one indoor unit mounted on a wall and one outdoor unit. It's the most popular and affordable choice for cooling a single room or an open-plan living area.

• Lower upfront cost and quick to install.
• Great for bedrooms, living rooms, or a home office.
• Each unit is controlled separately.

Ducted systems

Ducted air conditioning hides the unit in your roof and pushes air through vents in each room. It cools the whole home discreetly and can be zoned so you only run the rooms you're using.

• Whole-home comfort with a clean, hidden look.
• Zoning saves running costs.
• Higher upfront cost and best fitted during a build or renovation.

Which should you pick?

If you want to cool one or two rooms affordably, a split system is usually the smart start. If you're building, renovating, or want every room comfortable from one controller, ducted is worth the investment. A licensed installer can size either correctly for your home.

Air conditioner capacity is measured in kilowatts (kW). Getting the size right matters — an undersized unit runs flat out and never quite cools, while an oversized one cycles on and off, wasting energy and leaving the air clammy.

What affects the size you need

• Room size (floor area and ceiling height).
• Windows and sun: large or west-facing windows add heat load.
• Insulation in the walls and roof.
• Use: a kitchen or a room full of people needs more capacity.

A rough starting point

As a very rough guide, a small bedroom might need around 2–3.5kW, a medium living area 3.5–6kW, and a large open-plan space 6–9kW or more. This is only a starting point — sun, insulation, and layout can shift it a lot.

Get a proper calculation

A good installer does a heat-load calculation rather than guessing. It costs nothing extra and makes sure your system is comfortable, quiet, and cheap to run for years.

If you want to cool more than one or two rooms, the choice usually comes down to a ducted system or a multi-split system. Both work well — they suit different homes.

Ducted air conditioning

One central unit in the roof feeds air to vents throughout the home. With zoning, you control which areas run.

• Cleanest look — only slim vents are visible.
• Best for whole-home comfort from one controller.
• Higher upfront cost; ideally fitted during a build or reno.

Multi-split systems

One outdoor unit runs several indoor units (wall-mounted heads) — one per room. Each room is controlled separately.

• No bulky ductwork, so it suits existing homes.
• Independent control and temperatures per room.
• Indoor heads are visible on the walls.

Which suits you?

Choose ducted if you're renovating and want a seamless, whole-home finish. Choose multi-split if you want to cool several specific rooms in an existing home without major ceiling work. An installer can price both for your layout.