Melbourne’s housing stock spans over 150 years of construction, and the ducted systems installed in those homes reflect every generation of HVAC technology from the 1960s to the present. Understanding the type of ducted system in your home is the foundation for making informed decisions about cleaning frequency, maintenance requirements, and what a professional service actually involves for your specific setup.
This guide covers the main ducted system types found in Melbourne homes, how to identify which one you have, and how the system type affects cleaning requirements and intervals.
Ducted Gas Heating
Ducted gas heating is the dominant heating system in Melbourne residential properties — installed in the vast majority of homes built from the 1960s through to the late 2000s, and still common in new builds today.
How it works
A natural gas furnace unit (typically in the roof space, garage, or a dedicated utility area) burns gas to heat a heat exchanger. A fan draws return air from the home through the return air grille and filter, passes it over the heat exchanger, and distributes the warmed air through a network of supply ducts to ceiling or floor registers throughout the home. The entire duct network — return duct, main trunk, and supply branches — is what FreshDuct cleans in a standard residential service.
Identifying a ducted gas heater
The system unit will have a metal flue pipe exiting through the roof or an external wall. It will have a gas connection (usually flexible gas hose entering the unit). The unit is typically a rectangular metal box 600mm to 900mm long. Modern units have an energy rating label showing star ratings for gas efficiency. Ducted gas heaters produce warm, dry air — unlike evaporative coolers which produce moist air.
Cleaning requirements
Standard ducted gas heating duct cleaning covers the full duct network: supply branches, main trunk line, return air duct, and all registers. The filter is replaced. The cleaning process takes 2 to 3 hours for a 3 to 4 bedroom Melbourne home. See our full guide on ducted gas heating duct cleaning in Melbourne.
Carbon monoxide safety note
Ducted gas heaters have a heat exchanger that can crack with age, allowing combustion gases including carbon monoxide to enter the duct system. The mandatory 2-year gas service for Victorian rental properties and the recommended 2-year service for all Melbourne homes specifically inspects for this risk. See our guide on carbon monoxide risk from ducted gas heating.
Evaporative Cooling Systems
Evaporative cooling is extremely common in Melbourne — the city’s low summer humidity (relative to Sydney or Brisbane) makes evaporative cooling highly effective for most of the cooling season. Many Melbourne homes have an evaporative cooling unit installed on the roof alongside or instead of refrigerated cooling.
How it works
An evaporative cooler draws outdoor air through water-saturated cooling pads. As the air passes through the wet pads, water evaporates, cooling the air by 8 to 12 degrees Celsius. The cooled, humidified air is distributed through the duct network. Evaporative cooling requires windows or doors to be slightly open to allow warm indoor air to escape — it works by air replacement rather than air recirculation.
Identifying an evaporative cooler
The unit is mounted on the roof and connected to a water supply line. It is typically a square or rectangular white or cream-coloured box 600mm to 900mm across with vented sides. There is no outdoor compressor unit (unlike reverse-cycle systems). Supply registers are typically larger than those for heating systems to accommodate the higher air volume required for evaporative cooling.
Cleaning requirements
Evaporative cooling systems have additional cleaning scope compared to gas heating: the cooling pads are removed and replaced or cleaned, the internal water distribution manifold is inspected and cleaned, the internal water tray is cleaned to remove mineral scale and biological growth, and the blower is inspected. The duct network is also cleaned by negative pressure extraction. Total service time is typically 30 to 60 minutes longer than an equivalent gas heating clean. See our dedicated guide on evaporative cooling duct cleaning in Melbourne.
Ducted Reverse-Cycle Systems
Ducted reverse-cycle systems provide both heating and cooling from a single system, making them increasingly the preferred choice for Melbourne new builds and major renovations. They use refrigerant heat pump technology — the same principle as a split system air conditioner, scaled up for whole-house distribution.
How it works
An outdoor compressor unit circulates refrigerant to an indoor air handler unit (typically in the roof space). In cooling mode, the refrigerant absorbs heat from indoor air passing over the indoor fan coil and rejects it outside. In heating mode, the process reverses — heat is extracted from outdoor air and delivered inside. A ducted network distributes conditioned air from the indoor unit to all rooms.
Identifying a ducted reverse-cycle system
There will be an outdoor compressor unit (similar to a split system outdoor unit but larger) connected by refrigerant pipes to an indoor air handler in the roof space or ceiling cavity. The system produces both heating and cooling from the same registers. There is no gas connection and no roof-mounted evaporative unit. Energy rating labels will show both heating and cooling star ratings.
Cleaning requirements
In addition to the full duct network cleaning, a ducted reverse-cycle service includes inspection and cleaning of the indoor fan coil unit, which accumulates dust on its fins and can develop mould in the condensate pan. A blocked or fouled fan coil significantly reduces the system’s efficiency in both heating and cooling modes. The condensate drain is also checked and cleared. See our guide on ducted refrigerated cooling duct cleaning in Melbourne.
Older and Less Common System Types in Melbourne
Ducted electric heating
Some older Melbourne homes (1960s to 1980s) have ducted electric strip heaters — electric resistance elements in the air stream rather than a gas furnace. These systems are increasingly rare and inefficient by modern standards. The duct cleaning process is similar to gas heating, without the combustion safety considerations.
Hydronic heating (not ducted)
Hydronic heating — where hot water is circulated through radiator panels or underfloor pipes — does not use ductwork and is not covered by duct cleaning services. Melbourne has a significant stock of hydronic systems in period homes and apartment buildings. If your home has radiator panels rather than air registers, duct cleaning does not apply.
Central plant systems (apartments)
High-rise Melbourne apartments often have central plant systems where heating and cooling are provided from a building-wide plant room. Individual apartment duct cleaning is typically the responsibility of the building owner’s facilities management. Contact your building manager or owners corporation for maintenance information.