Why mould appears in air conditioners
When a split system cools, moisture condenses on the indoor coil and drains away. Dust and dirt that collect on the filters, coil, fan and drain give that dampness something to cling to. Over time, that can lead to visible mould and a musty smell.
Common contributors
- Filters and internal parts that haven't been cleaned in a long time.
- A blocked or slow condensate drain.
- Heavy use in humid weather.
- Dusty homes, pet hair and nearby building work.
What you can safely do yourself
- Turn the system off at the unit and the wall or breaker.
- Remove and rinse the reusable filters as shown in your manual, and let them dry fully before refitting.
- Wipe the visible outside of the indoor unit with a slightly damp cloth.
Avoid spraying liquids into the unit or opening panels beyond the filter access in your manual, as the inside contains electrical parts. See DIY vs professional aircon cleaning.
When to book a professional clean
If you can see mould or dark spots on the louvres or vents, or the unit smells musty, a professional clean is the next step. A Fresh Flow clean removes built-up dust, dirt and visible mould from the accessible parts of the system, flushes and checks the drain, applies an air-conditioning-safe sanitising treatment and finishes with an operational check. See what's included and our Bendigo prices.
When it's not a cleaning job
If you notice ice on the unit, a burning smell, repeated tripping of the power or a refrigerant leak, switch the system off and contact a licensed air conditioning technician.
Not sure the smell is mould? Read the signs your air conditioner needs cleaning.