Every Brisbane household that decides to air condition eventually arrives at the same fork in the road: a handful of split systems, or one ducted system serving the whole house. Salespeople tend to answer this based on what they prefer to install. The honest answer depends on your house, your budget, how you actually live in your home, and how long you plan to stay in it.

This article compares the two approaches across the criteria that matter in South East Queensland.

 

The two systems in plain terms

A split system has an indoor head mounted on a wall and an outdoor condenser, joined by refrigerant pipework. Each system cools one space. A multi-head split connects two to five indoor heads to a single outdoor unit.

A ducted reverse-cycle system hides a large fan coil in the roof cavity. Insulated flexible ducting runs from that fan coil to vents in the ceiling of each room. Motorised dampers create zones, so you can direct air to the bedrooms at night and the living areas by day. A wall controller or app runs the whole house.

Both use the same underlying refrigeration cycle and both are reverse-cycle, meaning they heat as well as cool — which matters more in Brisbane than people expect, because inland suburbs such as Ipswich, Springfield and the Lockyer fringe regularly drop below 5°C on winter mornings.

 

Upfront cost

This is where most decisions are made.

• One 5 kW split system in a living room: roughly $1,900–$2,900 installed
• Three split systems (living room plus two bedrooms): roughly $5,000–$7,500 installed
• Multi-head system with three heads: roughly $6,000–$9,500 installed
• Ducted system, four to six zones, in a typical 200 m² Brisbane home: roughly $11,000–$20,000 installed

Splits win decisively on entry price. Crucially, splits can be staged: install the living room now, the main bedroom next year, the kids’ rooms when the budget allows. Ducted is a single, large, all-at-once commitment.

However, once a household needs five or more rooms conditioned, the gap narrows considerably, and ducted starts to look competitive on a per-room basis.

 

Running cost and efficiency

The common claim that “ducted is expensive to run” is only true when ducted is used badly. Modern inverter ducted systems with well-implemented zoning are efficient because a single large compressor operating at part load is thermodynamically efficient.

The real variables are:

Zoning quality. A ducted system with only two crude zones will over-condition unused rooms. A system with six properly balanced zones and a variable-speed fan can behave almost like individual splits.

Duct losses. Ducting sits in a Brisbane roof cavity that can reach 60–70°C in February. Cheap R1.0 ducting bleeds energy the whole way to the vent. Insist on R1.5 or better and on short, straight duct runs. This is one of the largest hidden efficiency differences between a good and a bad ducted installation.

Behaviour. Splits naturally encourage “cool the room I’m in.” Ducted encourages “cool the house.” That behavioural difference often costs more than the equipment difference.

For a household that occupies one or two rooms at a time, splits generally cost less to run. For a family that occupies most of the house simultaneously on a 36°C Sunday afternoon, ducted is often cheaper per square metre cooled.

 

Aesthetics and the Queenslander problem

Ducted wins on looks. Only slim ceiling vents and a small wall controller are visible. If you have restored VJ walls, high ceilings and picture rails in a Paddington or Wooloowin Queenslander, a white plastic box on the wall is a genuine visual compromise.

But classic Queenslanders present a structural problem: many have shallow, unlined roof cavities with limited height above the ceiling joists, and some have decorative ceilings that cannot be cut. In those homes ducted may require bulkheads, under-floor ducting, or simply may not be feasible. Brick-and-tile homes in Carindale, Aspley or Forest Lake almost always have ample roof space and are ideal ducted candidates.

Splits are also easier in units and townhouses where body corporate approval limits roof and facade works.

Zoning and control

Splits give perfect independence: each room has its own thermostat, its own schedule, and its own on/off decision. If one unit fails, the rest of the house is unaffected.

Ducted gives centralised control and, increasingly, sophisticated app-based scheduling, temperature sensing per zone, and integration with home automation. The trade-off is a single point of failure. When a ducted compressor dies in January, the entire house is hot until the part arrives.

For Brisbane’s shoulder seasons — warm days, mild nights — splits are excellent because you can run one bedroom overnight at very low cost.

Noise

Splits place the fan coil in the room, typically producing 19–35 dB on low. Ducted places the fan coil in the roof, so the only in-room sound is air movement through the vent, often quieter and less directional. Light sleepers in bedrooms frequently prefer ducted.

Outdoors, ducted uses one larger condenser rather than several smaller ones. In tight inner-city blocks, one condenser is far easier to site in compliance with boundary noise limits than four.

Maintenance and repair

Splits: filters are user-cleanable, professional coil cleaning is straightforward, parts are cheap and widely stocked in Brisbane, and a failed unit can be replaced in a morning for a modest sum.

Ducted: filters are usually at a central return-air grille, which is convenient. But roof-cavity access for the fan coil is hot, cramped work, ducting can be damaged by rodents, and repairs cost more. Zone motors and dampers are additional failure points.

Mould is a real Brisbane concern for both. High humidity plus a cold coil equals condensation. Ducted systems with poorly sealed roof-space returns can draw dusty, humid air into the system. Annual servicing matters in this climate more than it does further south.

Resale value

Ducted reverse-cycle is a genuine listing feature in the Brisbane market and appears in agent copy for good reason. Splits are increasingly seen as expected rather than impressive. If you are renovating a family home you intend to sell within five years, ducted may return a meaningful share of its cost.

 

A practical decision framework

Choose split systems if:

• Your budget is under about $8,000
• You want to stage the work over several years
• You occupy one or two rooms at a time
• You live in a unit, townhouse, or a Queenslander with a tight roof cavity
• You rent, or plan to move within a few years
• You value redundancy — one failure should not disable the house

Choose ducted if:

• You are renovating or building and can integrate it into the works
• You want to condition five or more spaces
• Interior appearance matters to you
• You have adequate roof access and height
• Your household uses most of the house at once
• You plan to stay long term, or resale positioning matters

 

The hybrid approach nobody mentions

Many Brisbane homes end up with the smartest solution: ducted through the bedroom wing for quiet, even overnight comfort, plus a single high-capacity split in the open-plan living and kitchen area, which is the hardest space to condition and the one most often used alone. This lets you run a small, cheap system for evening living without firing up the whole house, and it gives you redundancy if either system fails.

Whichever direction you go, the installation quality will matter more than the badge on the front. Duct insulation, refrigerant charge, zoning design and condenser placement determine whether your system is a quiet, cheap background presence or a summer-long irritation.