Why duct cleaning comes up in Sydney homes
Ducts live in houses
Separate houses were 55.8% of Greater Sydney's homes at the 2021 Census. That's where ducted systems tend to be, and so where the question of cleaning them comes up.
Humid summers and musty smells
Observatory Hill's January afternoons average 60% humidity. Mitsubishi Electric says dirt inside an air conditioner can cause odours, help mould grow and clog the drain, so a smell that follows the airflow may begin in the indoor unit, not the ducts.
Heavy summer use out west
Penrith averages 67 days a year above 30 degrees, so a western Sydney ducted system moves a lot of air through its return air filter. Keep that filter clean and much of the dust stops there.
Roof space work
WorkSafe Victoria reports workers falling through plaster ceilings, and tells them to lay crawl boards across the joists and use battery-powered lights. A cleaner working in your roof should arrive with both.
Check these before you pay for a clean
The return air filter, behind the large grille that draws air back to the unit. On ducted gas heaters, Seeley's technician guide names a dirty return air filter among the common causes of overheating faults.
The indoor unit. On ducted reverse cycle, have the coil and drain looked at during a service if the smell is musty. See air conditioning service in Sydney.
The ducts' condition. A room that's always weak often points to a crushed or disconnected duct in the roof, and cleaning won't fix that. Our ducts and vents page explains the repairs.
We haven't found an official rule on how often household ducts should be cleaned, so treat a fixed schedule on a flyer with suspicion. The national duct cleaning page covers what a proper clean involves.
Ask a Sydney duct cleaner
- Will you inspect the system before you quote?
- How do you clean flexible ducting without tearing the liner?
- Do you bring crawl boards for the roof space?
- Will you give me photos of any damaged or disconnected runs?
- Should the indoor unit or heater be serviced at the same visit?
What you can clean, and what you can't
You can
- Vacuum or wipe the outlet grilles you can reach from the floor.
- Clean the return air filter as your manual says, with the system off.
- Note whether the smell or dust comes with heating, cooling or both.
Leave to a licensed installer
- Anything inside the duct runs or in the roof space.
- Cleaning inside the indoor unit or a gas heater.
- Repairing damaged ducts.
What we'd do
Where we'd start
Filter and grilles first, a service if the smell is musty, and a duct clean only when there's a clear reason. If we booked one, we'd want a duct specialist who inspects before quoting and reports with photos, and if the ducts turned out to be damaged rather than dirty, we'd have them repaired instead. Tell us what you're seeing and we'll pass it to the right kind of specialist, where we have one near you.
