The first time I stored a window AC unit, I just dragged it into the garage and left it. Next summer it rattled, smelled like dust, and blew lukewarm air. A little prep the fall before would have saved me a repair bill.

Why storage matters

AC units collect dust, moisture, and sometimes bugs while they sit. If you store one dirty and damp, all of that waits for you in June.

How to store it the right way

1. Unplug the unit and remove it from the window on a dry day.
2. Wipe down the filter, and vacuum the fins gently.
3. Let it drain and dry completely for a day.
4. Cover it with a fitted cover or a sealed plastic bag, then store it upright.

Never store an AC unit on its side or its back. The compressor needs to stay upright, or oil can shift where it should not be.

What I learned

I now keep the original box or a fitted cover, and I label which room the unit came from. It takes half an hour in the fall and saves me an hour of troubleshooting every spring.

Also, run the unit on fan-only for a few hours before you pull it, to dry out any inside moisture.