Ducted vs Split System Air Conditioning: Which Is Best?

Choosing between ducted and split system air conditioning is one of the most important decisions for your new home. Here's a comprehensive comparison.

Quick Comparison

Ducted Air Conditioning

How It Works

A ducted system has a central indoor unit (usually in the ceiling) connected to an outdoor compressor. Conditioned air is distributed through ducts to vents (grilles) in each room. Zones allow you to turn airflow on/off to different areas.

Advantages

• Aesthetics — only ceiling grilles visible, no wall units
• Whole-home comfort — every room is air conditioned
• Zoning — control which rooms receive airflow (saves energy)
• Even distribution — better air circulation than wall units
• Smart control — modern systems integrate with home automation

Disadvantages

• Higher cost — significantly more expensive than splits
• Energy losses — ductwork loses 10–20% of cooling through the roof space
• Ceiling space — requires sufficient roof cavity for the indoor unit and ducts
• Less individual control — zones control groups of rooms, not individual temperatures

Cost Breakdown

• System + installation (3-bedroom home): $8,000 – $12,000
• With zoning (4+ zones): $10,000 – $15,000
• Premium brands (Daikin, ActronAir): $12,000 – $18,000+
• Add smart home integration: $500 – $1,500

Split System Air Conditioning

How It Works

A split system has an indoor wall unit connected to an outdoor compressor via refrigerant piping. Each indoor unit cools a single room.

Advantages

• Lower cost — much cheaper than ducted for the same number of rooms
• Individual control — each room has its own thermostat
• Higher efficiency — no ductwork losses
• Easier installation — no ceiling ductwork needed
• Flexibility — can add more units later
• Easy maintenance — filters accessible on each unit

Disadvantages

• Wall units visible — not as aesthetically clean as ducted
• One room per unit — a large home needs many units
• Outdoor space — each indoor unit needs an outdoor unit (or a multi-split system)
• No whole-home airflow — doesn't circulate air between rooms

Cost Breakdown

• Single room (2.5kW): $1,000 – $1,500 installed
• Living area (5–7kW): $1,800 – $2,800 installed
• Large living (8–10kW): $2,500 – $3,500 installed
• Multi-split (2–3 indoor units, 1 outdoor): $4,000 – $7,000

Hybrid Approach: The Best of Both

Many new home builders choose a hybrid approach:

1. Ducted system for the main living areas and master bedroom
2. Split systems in children's bedrooms, study, and minor rooms

This provides whole-home comfort in the main living spaces while keeping costs down in less-used rooms. It also allows individual temperature control in bedrooms.

Sizing Your System

Proper sizing is critical — an oversized system short-cycles (poor humidity control), and an undersized system can't keep up on hot days. A professional installer will calculate the required capacity based on:

• Room size and ceiling height
• Window size and orientation
• Insulation levels
• Local climate
• Number of occupants

As a rough guide:

• Bedroom (12–18m²): 2.5kW
• Living room (25–40m²): 5–7kW
• Open-plan living (40–60m²): 7–10kW
• Whole home (ducting): 12–20kW

Installation During Your Build

Installing air conditioning during construction has several advantages:

• Ceiling access — ductwork can be installed before plasterboard
• Electrical rough-in — wiring can be planned and installed properly
• Builder coordination — your builder can accommodate the system design
• Cleaner installation — no cutting into finished walls/ceilings

Discuss air conditioning with your builder early. Some builders include ducted air conditioning as an upgrade; others leave it for you to arrange.

Find an ARC-licensed air conditioning installer on Trade Connect or read our guide on ducted vs split systems.