The quick answer
To store a portable air conditioner for winter: drain it completely, clean the filter, run fan-only mode for an hour so the inside dries, wipe down the casing, coil up the hose, and keep the unit upright in a dry place that does not freeze. The whole job takes about two hours, most of it waiting for things to dry.
End-of-season checklist
| Task | Why | Time |
|---|---|---|
| Clean the filter | Dust left on a stored filter can hold moisture and smell | 30 min incl. drying |
| Drain all water | Stops mould and freeze damage | 15 min |
| Run fan-only | Dries the coils and the inside | 60 min |
| Wipe the casing | Removes dust before it sets | 10 min |
| Store hose and kit | Prevents cracks and lost parts | 15 min |
| Keep the manual | You will want it in May | 5 min |
Drain and dry it
- Switch off and unplug. Leave it for 30 minutes.
- Drain the tank. Remove the drain plug and empty into a tray. Check for a second drain at the base.
- Tilt gently. Tip the unit slightly backwards over the tray to release trapped water, then set it upright again.
- Run fan-only. Plug it in without the exhaust hose and run fan or dry mode for about an hour in a ventilated room.
- Unplug and let it stand. Leave it for a few hours before covering it.
Hose, window kit and remote
- Hose: wipe it clean, check for splits and coil it loosely in a bag. Do not crush it flat.
- Window kit: clean the panels, check the foam seals and store them flat so they do not warp.
- Remote control: take the batteries out to avoid leaks and keep it with the manual.
- Label the bag. Keep every part together so nothing goes missing by next summer.
Where to store it
Good places
- A spare room, cupboard or under-stairs space
- A dry, heated loft or boarded roof space
- Anywhere upright, level and above freezing
- Under a breathable dust cover or sheet
Avoid
- An unheated garage or shed
- Damp utility rooms or cellars
- On its side, or with items stacked on top
- Plastic bags that trap moisture around the unit
Humidity is the UK's main storage problem. If the space is damp, add a moisture absorber and check the unit mid-winter for condensation.
Starting it again in spring
- Inspect it. Look for damp, mould smells, cracks in the hose and missing parts.
- Let it reach room temperature. If it was stored cold, leave it for a few hours.
- Clean the filter and refit it, then fit the window kit and hose. See how to install a portable air conditioner.
- Run it. Start in fan-only for 30 minutes, then switch to cooling and watch the first cycle.
If a unit has failed, spring is also the time to compare replacements. See the how to choose a portable air conditioner guide.
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