Why is my air conditioner blowing out black specks?

Air Conditioner Blowing Black Specks?

The short answer

Black specks are almost always mould and grime from inside the unit. Dust that gets past the filters sticks to the damp coil and fan barrel, mould grows on it, and the fan throws flakes out into the room. It usually comes with a musty smell. A spray from a can won't shift it. The coil, fan barrel and drain tray need a proper clean.

Where the specks come from

In cooling mode, the indoor coil pulls water out of the air and stays damp. Fine dust, cooking grease and pet hair that slip past the filters stick to the wet surfaces, and mould grows on the mix. The fan barrel, the long cylindrical fan behind the louvres, collects the worst of it. As it spins, it flicks black flakes onto walls, bedding and the louvres themselves.

Units that run long hours, sit in steamy rooms, or are switched off straight after cooling on muggy days tend to grow more. Shine a torch through the louvres: a fan barrel coated in black or furry grey is the source.

Smell and health

A musty or sour smell when the unit starts comes from the same growth. People with allergies or asthma may notice their symptoms when it runs. Until it's cleaned, use the unit less in bedrooms and keep the filters clean. If anyone in the house is unwell, keep it off and ask your doctor for advice.

Why it needs a proper clean

Off-the-shelf sprays reach the front of the coil but not the fan barrel or the drain tray, and the loosened grime often blocks the drain or blows out later. Liquid in the wrong place can also wet the electronics. A proper clean protects the electrics, then washes the coil, fan barrel and drain tray, with the dirty water caught and drained away. Clean filters, and running the fan or dry mode for a while after cooling if your unit has one, help slow the regrowth.

What you can safely do now

Turn the unit off and wipe visible specks from surfaces with a damp cloth.
Clean the dust filters if your manual shows how and you can reach them safely.
Shine a torch through the louvres to look at the fan barrel, without reaching inside.
Avoid spraying cleaners or disinfectants into the unit.

Services that can help

Split System Cleaning & ServicingFilters, drainage, airflow and operation checked before peak use.Ducted Air Conditioning CleaningFilters, return grilles and outlets cleaned for better airflow.