Ducted vs Split System Air Conditioning: Which Is Right for Your Home?

Air conditioning accounts for up to 40% of a home's energy bill in Australian summers. Choosing the right system type — ducted or split — affects your comfort, your energy costs, and your home's value for years to come.

Split System Air Conditioners

A split system consists of an indoor head unit (wall-mounted or ceiling cassette) connected to an outdoor compressor unit. Each indoor unit operates independently. A multi-split system uses one outdoor unit to serve multiple indoor heads.

Advantages:

• Lower upfront cost: A quality single split system (5–8 kW) typically costs $1,500–$3,500 installed. A multi-split serving 4 zones costs $6,000–$10,000.
• Zone control: Each room's unit runs independently — only cool what you're using.
• Efficiency: Modern inverter split systems are highly efficient, with COP (Coefficient of Performance) ratings of 3.5–6.0.
• Easy installation: No ductwork required — can be added to existing homes without major building work.

Disadvantages:

• Multiple indoor units require multiple wall penetrations and can look cluttered in some rooms
• Not ideal for open-plan homes where one large area needs cooling
• Each indoor unit is visible and must be considered in room design

Ducted Air Conditioning

A ducted system uses a central unit (typically in the roof space or under the floor) connected to rooms via insulated ducts. Air is distributed through ceiling or floor vents. Modern systems include zone control, allowing you to select which areas are cooled.

Advantages:

• Whole-home comfort: Cools every room evenly from a single system
• Aesthetics: Only small vents visible — no wall units in every room
• Property appeal: Ducted aircon is a strong selling point for most Australian buyers
• Zoning: Modern ducted systems with smart zoning let you control individual rooms or areas

Disadvantages:

• Higher upfront cost: Full whole-home ducted system: $8,000–$18,000 installed depending on home size and number of zones
• Duct heat gains: Ducts in roof spaces can absorb heat — insulated, well-installed ducts minimise this
• Less efficient for partial use: Running a ducted system for just one room wastes energy compared to a split system

How to Choose

Choose split systems if:

• You're in a rental or can't do significant building work
• You only need to cool 1–3 rooms
• Budget is a primary constraint
• You want to minimise running costs through granular zone control

Choose ducted if:

• You're building a new home or doing a major renovation (ductwork is far cheaper to install at this stage)
• You want whole-home comfort and aesthetics
• Your home has 4+ bedrooms and open plan living areas
• You're optimising for property value

Energy Efficiency and Running Costs

For the same cooling capacity, a modern split system is typically more efficient than a ducted system when running a single zone (due to duct losses). However, when cooling the whole home, ducted systems using inverter technology and smart zoning can be equally efficient.

Key efficiency ratings to look for:

• Star rating: More stars = more efficient. Look for 5–6 stars on Australian Energy Rating labels.
• AEER (Annual Energy Efficiency Ratio): Cooling efficiency. Higher is better.
• ACOP (Annual Coefficient of Performance): Heating efficiency. Higher is better.