What to Clean Before You Put Your Air Conditioner Away

As mornings and evenings cool down, the AC remote goes back in the drawer. But next summer’s AC smell is mostly decided now. All summer, the inside of the unit has been wet with condensation from cooling. Leave that moisture inside for months and mold quietly grows.

1. Wash and dry the filter

The filter holds a summer’s worth of dust, and dust holds moisture and feeds mold. Wash it before storage and let it dry completely in the shade before refitting. See how to clean an air conditioner filter.

2. Dry the inside with fan mode

With the filter back in, run fan mode for 1–2 hours. This dries the hidden coils and drain pan. Even if your unit has an auto-dry feature, a final long fan run is the safest option. Doing it on a clear, dry day with the windows open works even better.

3. Clear around the outdoor unit

Remove leaves, plastic and objects around the outdoor unit. Debris that collects over winter can jam the fan or block heat release when you start it again. If you cover it, choose a cover that protects only the top; wrapping it completely can trap moisture and cause corrosion.

4. Cover the indoor unit

A dust cover on wall-mounted or floor-standing units makes next year’s cleaning much easier. Only cover it once the inside is completely dry; covering it wet traps the mold in.

5. Unplug and remove remote batteries

Unplug the unit during the off-season to save standby power, and take the batteries out of the remote. Batteries left in for months can leak and corrode the contacts.

Signs it needs a professional

If any of these apply, cleaning the filter is not enough. Consider a professional deep clean.

• Black spots on the louvers or fan inside the vent
• A sour smell as soon as it starts, even after washing the filter
• Water dripping from the unit
• No deep clean in two or three years

AC cleaning services are busiest in early summer. Booking in autumn or spring means less waiting.