At a Glance
Brisbane's subtropical climate puts heavy demands on air conditioning, and ducted systems are the preferred solution for whole-home cooling. Expect $7,200–$19,800 per system, with the range driven by house size, roof space conditions, humidity-adjusted sizing, and whether existing ductwork can be reused.
What's Included in the Price
- Supply and install of outdoor compressor and indoor fan coil unit
- Ductwork fabrication and installation to AS 4254.1 Ductwork for Air-Handling Systems
- Ceiling diffusers, return air grilles, and zone dampers (if multi-zone)
- Refrigerant piping, drainage, and condensate management
- Electrical connection and dedicated circuit to AS/NZS 3000 Wiring Rules
- Controller installation, system commissioning, and airflow balancing
- Electrical Safety Certificate lodged with the Queensland Electrical Safety Office
Brisbane's humidity means condensate drainage is a more significant consideration than in drier climates. A good installer will ensure adequate drainage fall and consider a condensate pump if gravity drainage is not feasible.
What Affects the Cost
- Humidity-adjusted system sizing. Brisbane's subtropical climate means the system must handle both temperature and moisture. This latent cooling load often requires a larger capacity unit than the same floor area in a drier city.
- Roof cavity temperatures. Tin and metal roofs, common across Brisbane, can push cavity temperatures above 60°C in summer. Ductwork needs high R-value insulation and vapour barriers to prevent heat gain and condensation. This adds to material costs.
- House construction type. Timber-framed homes (including Queenslanders) are easier to route ductwork and piping through than brick or masonry. However, high-set Queenslanders with complex rooflines may have limited duct routing options.
- New install vs replacement. Replacing an existing ducted system reuses penetrations and routes, saving 30–40%. But ductwork in Brisbane's climate degrades faster than in cooler cities — flex duct in a hot tin roof cavity may only last 10–12 years before insulation deteriorates.
- Zoning. Multi-zone control is particularly valuable in Brisbane where open-plan living areas dominate. Zoning lets you cool the living space during the day and switch to bedrooms at night without running the entire system.
- Three-phase power. Larger homes need systems above 12kW, which require three-phase. Energex manages the supply upgrade.
- Condensate management. High humidity means more condensation from the indoor unit. If gravity drainage is not possible, a condensate pump is needed, adding a small but necessary cost.
A replacement system in a single-storey, 3-bedroom lowset home with good roof access, serviceable existing ductwork, and single-zone control sits toward $7,200. A new installation in a large Queenslander with tin roof, high-R ductwork requirement, 4-zone control, three-phase upgrade, and premium unit pushes toward $19,800.
Brisbane-Specific Considerations
Brisbane's climate makes ducted air conditioning less of a luxury and more of a necessity. Summer temperatures regularly exceed 35°C with high humidity, and the cooling season stretches from October through April. A ducted system that can handle this sustained load needs to be correctly sized — undersized systems run constantly, driving up energy bills and wearing out faster.
The traditional Queenslander presents a unique installation scenario. These high-set timber homes have generous roof cavities that can accommodate ductwork, but tin roofing sends cavity temperatures soaring. Ductwork in these conditions needs R1.5 or higher insulation with proper vapour barriers to prevent both heat gain and condensation. Without adequate insulation, cooled air picks up heat before it reaches the room — wasting energy and reducing comfort. Flex duct in these conditions degrades faster than rigid duct, so expect replacement every 10–12 years rather than the 15–20 year life you might see in a cooler climate.
Newer developments in Logan, Springfield, North Lakes, and Caboolture are designed with ducted air conditioning as a standard feature. These homes have engineered roof trusses with ample cavity space, modern insulation, and pre-wired electrical. Installation in these properties is faster and cheaper than retrofitting an older home.
For homes in flood-prone areas (parts of Rocklea, Graceville, and low-lying Brisbane River suburbs), the outdoor compressor unit placement matters. It should be elevated or positioned where floodwater is unlikely to reach it. Discuss this with your installer during the site inspection.
Hiring a Licensed Air Conditioning Technician in QLD
Ducted air conditioning installation requires an ARC (Australian Refrigeration Council) authorisation for refrigerant handling. The electrical work must be done by an electrician licensed through QBCC, who must lodge an Electrical Safety Certificate with the Electrical Safety Office.
Air conditioning installation in Queensland also requires a QBCC licence for mechanical services. Verify that your installer holds both QBCC and ARC credentials. You can check licences on the QBCC and ARCtick websites.
Get at least three quotes. A proper quote should follow an on-site inspection where the installer measures the roof cavity, checks insulation, assesses electrical capacity, and discusses humidity management. Any quote given without a site visit in Brisbane should be treated with scepticism — humidity-adjusted sizing cannot be done from a floor plan alone.
How We Calculate
Estimates are based on surveyed trade rates for licensed air conditioning technicians in the Brisbane metro area, adjusted for property type and climate considerations. All prices include GST. Figures cover standard residential ducted air conditioning systems only.