How do you get mold out of a mini split?

What you can clean yourself, and what needs the head taken apart.

Getting mold out of a mini split

Turn the unit off at its breaker, take out and wash the filters, and wipe the vanes and the opening you can reach. Mold on the blower wheel or deep in the coil needs a deep cleaning with the head partly taken apart and bagged so the rinse water drains away. The EPA advises not running a system you think holds mold.

Then fix why it grew, or it comes back.

Signs there's mold in the head

A musty or sour smell when it starts, worst in cooling mode

Black or grey specks on the vanes or around the air outlet

Dark buildup on the blower wheel, the striped drum you can see behind the vanes with a flashlight

Water dripping from the head instead of draining outside

What you can clean yourself

1

Shut it off

Turn it off at the remote, then at the breaker or disconnect, so the fan can't start while your hand is in it.

2

Wash the filters

Lift the front panel, slide out the mesh filters, and wash them in warm soapy water. Let them dry fully before they go back.

3

Wipe what you can reach

Wipe the vanes, the panel and the outlet with a damp cloth and mild detergent. Don't spray cleaners into the electronics.

If a quick look with a flashlight shows the blower wheel is coated, stop there. Scrubbing it in place mostly pushes the mold deeper.

What a deep cleaning involves

The head's covers come off, a drain bag goes under it, and the coil and blower wheel are cleaned with a coil cleaner and rinsed until the water runs clear. The condensate drain line is flushed, since a slow drain is often where the problem starts. On some heads the blower wheel comes out to be cleaned on its own.

Why it grows, and how to keep it from coming back

Mold needs moisture and dust. A mini split cooling a room makes both: water on the coil, and dust the filter didn't catch. A few habits keep it down:

Rinse the filters about once a month while it's running hard

After cooling, run Fan or the unit's dry or clean cycle for a while so the coil dries

Keep the drain line clear; water in the head is a warning

Don't oversize: a unit that short-cycles leaves the coil wet (see oversized condensers )
If anyone in the house has asthma or allergies, or the mold covers a large area, get help rather than doing it yourself. Our ductless page covers service as well as installs.

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