Ducted Heating in Melbourne: Gas or Reverse-Cycle?
“Ducted heating” can mean a gas heating system or an electric reverse-cycle system. Both distribute warm air through ducts, but they are different installations.
If you are replacing gas heating with reverse-cycle, ask the installer to separate the new system and installation from gas disconnection, removal of the old equipment, ductwork changes and any electrical upgrades. That makes it easier to see what the quote covers.
For a gas-to-reverse-cycle conversion, ask the installer to assess the ductwork requirements and itemise the proposed ductwork, including its size, insulation and layout. The Victorian Government's reverse-cycle buying guide explains what to discuss with your installer.
For a Melbourne home, the quote should identify both heating and cooling capacity, which rooms each zone serves, and any work needed to fit the system into the roof space. If a discount is included, ask for the full installation total and the discount to be shown separately.
What Affects the Cost
Heating and cooling capacity. Melbourne's climate demands a system sized for both extremes. Installers size for winter heating demand, which often requires a larger unit than the same floor area would need in Sydney or Brisbane for cooling alone. A 4-bedroom home typically needs 12–15 kW.
Double-brick construction. Common in Melbourne's eastern suburbs (Balwyn, Box Hill, Glen Waverley), double-brick walls make routing refrigerant piping and electrical cable harder than in timber-framed homes, adding a half-day or more in labour.
Roof cavity height. Victorian-era and Edwardian homes in inner suburbs often have low-pitch or complex roof lines with limited cavity space, making ductwork installation difficult and sometimes requiring slim-line indoor units.
Zoning and smart control. Multi-zone control is particularly valuable in Melbourne where you might heat only the living areas during the day and switch to bedrooms at night. Smart controllers like
AirTouch 5 or
iZone run $2,500–$4,500 installed and typically pay for themselves within 3–5 years.
Gas ducted heating conversion. Many Melbourne homes have Braemar or Brivis gas ducted heating. Converting to reverse-cycle electric involves replacing the gas unit and assessing the existing ductwork's size, insulation and condition. Ductwork replacement is generally recommended, particularly when switching from gas.
Three-phase power. Larger homes (4+ bedrooms) with systems above 12kW may need a three-phase upgrade through
CitiPower and Powercor, adding $3,000–$5,000.
Insulation quality. Melbourne's temperature extremes make insulation particularly important. A well-insulated home can run a smaller, cheaper system. Poor insulation means oversizing the unit and paying more to run it year-round.
A replacement system in a single-storey, 3-bedroom timber-framed home with good roof access, existing ductwork routes, and single-zone control sits toward $7,800. A new installation in a 4-bedroom double-brick home in Balwyn with low roof pitch, 4-zone smart control, three-phase upgrade, gas system removal, and premium reverse-cycle unit pushes toward $21,600.
Melbourne-Specific Considerations
Melbourne's four-season climate makes it the strongest market for ducted reverse-cycle air conditioning in Australia. Unlike Sydney or Brisbane where cooling is the primary concern, Melbourne homeowners need a system that heats efficiently through winter and cools through summer. The system must be sized for the harder job, which in Melbourne is often winter heating, not summer cooling.
The inner suburbs present the biggest installation challenges. Victorian-era terraces in Fitzroy, Carlton, and Richmond have complex roof lines with limited cavity space. Edwardian homes in Northcote and Thornbury are slightly better, but still require careful duct routing. These properties often end up with higher install costs and may need slim-line ducted units designed for tight spaces. A good installer will inspect the roof cavity before committing to a ducted solution, as some inner-city properties are genuinely better suited to multi-split systems.
The eastern suburbs (Balwyn, Box Hill, Doncaster, Glen Waverley) have a different challenge: double-brick construction. The roof space is usually adequate, but running piping and cable through or around solid brick walls takes more time. Many of these homes were built in the 1960s through 1980s with gas ducted heating systems approaching or past end of life. The conversion from gas to reverse-cycle electric is a growing trend, driven by both economics (reverse-cycle produces 3–5 units of heating per unit of electricity, significantly cheaper than gas) and the Victorian Energy Upgrades (VEU) program.
The VEU program offers discounts of up to ~$5,530 for replacing gas ducted heating with a ducted reverse-cycle system, or up to ~$7,200 for a multi-head split system replacement, with a $1,000 minimum co-payment. From 31 March 2025, all VEU-installed products must include a 5-year warranty, and the program has been extended to 2045. Combined with improved running costs (savings of up to $1,010 per year compared to gas ducted heating), the economics of switching are compelling. Your installer should be an accredited VEU provider and handle the paperwork as part of the quote.
Melbourne's growth corridors in Craigieburn, Pakenham, Tarneit, and Wyndham Vale are the easiest and cheapest suburbs for ducted installs. Newer homes are designed with ducted in mind: engineered roof trusses with ample clearance, pre-wired electrical, and modern insulation. Many builders offer ducted as a standard package or affordable upgrade during construction, typically at $3,000–$5,000 less than a retrofit installation.
Hiring a Licensed Air Conditioning Technician in VIC
Ducted air conditioning installation requires an ARC (Australian Refrigeration Council) authorisation for refrigerant handling (R32 in modern systems), and the electrical component must be completed by an electrician registered with Energy Safe Victoria. The electrician must issue a Certificate of Electrical Safety (CES) and lodge it with ESV within 30 days.
Worth checking:
Victorian electrical licence (verify on the ESV website)
That the quote specifies unit brand, model, capacity (kW), number of zones, ductwork R-value, and warranty coverage
If replacing gas, that the quote itemises gas disconnection and any ductwork removal or replacement needed after assessment
VEU rebate eligibility and whether the installer handles the application
CES confirmation before making final payment
Melbourne has a competitive installer market, so get at least three quotes. A good installer will conduct an on-site inspection covering roof cavity clearance, wall construction type, insulation, electrical capacity, and existing gas system removal requirements before providing a fixed-price quote.
How We Calculate
Estimates are based on surveyed trade rates for licensed air conditioning technicians in metropolitan Melbourne, adjusted for property type and construction era. All prices include GST. Figures cover standard residential ducted air conditioning systems. Commercial and industrial installations are excluded.