Ducted Air Conditioning

A standalone house is the most natural application for a ducted system. A pitched roof provides space for the indoor unit and ductwork, and the floor plan maps cleanly to zones.

For existing homes, we start with a roof cavity assessment to confirm clearance and map duct routing before quoting. For new builds and renovations, early involvement is the better approach: coordinating with your builder before the ceiling is closed means cleaner duct runs and no structural compromises. Learn more about our full residential air conditioning services.

Apartments are more complex territory, and the main practical challenge is the ceiling cavity. Many apartments in multi-storey buildings have concrete slab ceilings with no space for ductwork. In those cases a ducted system typically isn’t feasible, and a cassette or split system is the practical alternative.

For lower-density strata properties such as townhouses, villa units and ground-floor apartments with roof access, ducted is sometimes viable.

• Body corporate approval: Most strata schemes require written approval before any work affecting the building’s exterior, roof or common property.
• Noise and placement rules: Some by-laws restrict where outdoor units can be installed.
• By-law review: We can advise on what the installation involves physically, but strata approval is the owner’s responsibility.

Read more about our air conditioning for apartments service.

New builds are where ducted systems perform at their best. When air conditioning is designed into the build from the start, duct runs are shorter and more efficient, the indoor unit sits exactly where it should, and zones are mapped to the floor plan before anything is locked in structurally.

We work with builders, developers and owner-builders across all project scales, from single dwellings to multi-lot developments.

For offices, retail tenancies, warehouses and mixed-use spaces, ducted systems are often the right call when the ceiling structure allows. Commercial applications involve different capacity requirements and load profiles than residential applications.

We handle commercial air conditioning across Sydney, including ducted installations for fit-outs and tenancy upgrades.

• Dirty return air filter: A blocked filter is the most common cause of poor cooling. It restricts airflow to the indoor unit and reduces AC efficiency. Check and clean the filter first.
• Zones set incorrectly: If a zone isn’t open or the controller is set to the wrong mode, you may be heating instead of cooling.
• Refrigerant loss: Requires a licensed technician to diagnose and rectify.
• Blocked return air grille: Furniture or curtains placed too close will starve the system.
• Undersized system: If incorrectly sized for your home it will struggle on hot days regardless of condition.
• Duct damage: Air escaping into the roof cavity means rooms don’t cool even when the system is working correctly.

If a filter clean doesn’t resolve it, call 1300 507 892 and we’ll diagnose it properly.

A ducted system should be close to silent in the living areas. If you’re hearing noise, here’s what it usually means:

• Rattling or vibrating ducts: Often a loose flex duct connection, a duct touching a structural element, or debris in the ductwork.
• Banging or clunking at startup: Can indicate a loose component in the indoor unit or, in older systems, worn fan bearings.
• Whooshing or whistling at vents: Usually too many zones closed at once, forcing high-velocity air through fewer vents.
• Loud or persistent noise from the outdoor unit: Grinding, rattling or knocking that doesn’t settle warrants a service call.
• Squealing: Usually a fan belt or bearing issue in older systems.

Before calling a technician, run through this checklist:

• Power at the isolator: Check the external isolator switch is in the ON position.
• Circuit breaker: Check your switchboard for a tripped breaker on the AC circuit.
• Controller settings: Confirm the correct mode, that the set temperature is calling for action, and that at least one zone is active.
• Zone settings: If all zones are off, the system may not start.
• Fault code: If a fault code is displayed, check our error codes page before calling.

Don’t attempt to reset it repeatedly: if a fault is present, continued cycling can cause further damage.

A well-maintained ducted air conditioning system typically lasts 15 to 20 years. Lifespan depends on the quality of the original installation, how often the system is serviced, and how hard it runs. Systems that are regularly serviced and correctly sized for the home consistently outlast those that aren’t.

Yes. Most ducted systems are reverse cycle, meaning the same unit cools your home in summer and heats it in winter. Reverse-cycle ducted systems are the most common type installed across Sydney, and most systems Paragon supplies are reverse cycle unless otherwise specified.

In most residential cases in NSW, ducted air conditioning installation does not require council development approval. It is typically treated as exempt development under the State Environmental Planning Policy, provided the outdoor unit placement meets certain noise and setback requirements. You should check your local council’s requirements and any strata by-laws if applicable. Paragon can advise on what’s involved during the site assessment.

Sometimes, but it depends on what’s already installed. If your existing system uses a compatible zone controller and the ductwork can support additional dampers, adding zones is possible. Older systems or those installed with non-zoning-compatible components may not support it, or may require a controller upgrade. The easiest way to find out is to book a service visit and we’ll assess what’s in place.

Ducted systems are among the quietest options for whole-home air conditioning. The compressor sits in the roof cavity or outside the building, so there’s no fan noise inside the living areas. Airflow through well-designed ductwork is quiet. If you do hear noise from a ducted system, it usually indicates an issue rather than normal operation.

Paragon recommends servicing your ducted system once a year. An annual service keeps filters clean, checks that all zone dampers are operating correctly, and catches small issues before they become expensive repairs. In homes where the system runs heavily during summer, a pre-season service in spring is worth scheduling before the peak cooling period.

A zone that stops responding is usually caused by a faulty motorised damper, a wiring fault in the zone controller, or a controller board issue. In most cases it’s a straightforward repair. Until it’s fixed, you can continue using other zones normally. Call us and we’ll diagnose it properly.

Not in the conventional sense. Standard ducted systems require a roof cavity to house the indoor unit and run ductwork to each zone. Homes with flat roofs, skillion roofs, or concrete slab ceilings typically can’t accommodate a ducted system. In those cases, alternatives like cassette air conditioning or split systems are usually the right solution. A site inspection will confirm what’s possible for your specific property.

Yes, and in many ways a 2-storey home benefits more from a ducted system than a single-storey. The ability to zone upstairs and downstairs separately means you’re only conditioning the floor that’s in use, which in a typical household is a real efficiency gain. Ductwork routing across two floors is more involved than a single-storey install, and access to the upper-floor ceiling space needs to be assessed, but 2-storey homes are a common and very workable application for ducted systems.