How to Clean Your Window AC Unit in 8 Simple Steps

A mild soap or detergent is the best cleaning agent for your window AC unit. 3% hydrogen peroxide solution is also a suitable option, but due to the fact that it can be dangerous in large quantities, you’ll want to be careful about getting it on your skin. (Eyewear and gloves are also recommended if you use hydrogen peroxide.)

Avoid using bleach or even vinegar (two highly common cleaning products) for your air conditioner. Both corrode metal, which will wear down the device.

If your air conditioner isn’t working, you might consider calling a local AC repair specialist.

Unplug your window air conditioning unit before you start any cleaning. You don’t need to remove the device from the window (unless you want to). But if it’s positioned in a second-story window or the outside area is hard to access, you may want to remove it so you can clean the back and comb the fins.

Taking it out can also help you assess whether it’s time to repair or replace your AC.

Using your detergent, soap, or hydrogen peroxide, wipe down the outward-facing parts of your device. Spraying into a cloth or paper towel instead of directly into the device is best for accurate cleaning (and to avoid a longer dry time later).

Once you’ve wiped it down, you can detach the outside cover. Most AC window units have hooks or screws that need to be removed to get the case off.

The air filter should be covering the inside parts of your device once you take the cover off. Some window air conditioners have reusable filters, while others have disposable ones you’re supposed to replace every three to six months. If you’re unsure, look in your manual or do an online search for which type of filter your AC has.

If it’s reusable, wipe down your filter and remove all dirt and debris from it.

The U.S. Department of Energy recommends replacing or cleaning filters once a month. This keeps your device running efficiently, and ensures allergens like dust don’t get through into the air. Not replacing or cleaning your filters is one of the easiest ways to accidentally kill your air conditioner.

Often there is leftover dust and other particles hanging on the edge of where your filter sits inside the device, or maybe even behind it. Using an extension hose, vacuum these small areas. Touch each surface lightly to avoid denting or damaging parts of your machine.

If dirt buildup is excessive, it may be better to use a fresh cloth here and just wipe down the area.

The compressor fins are the sharp metal edges on the back of a window air conditioner that help push hot air away from the device when cooling a room or home. To clean and restore efficiency to your unit, it’s best to straighten these while you clean.

The fins can be sharp, so a fin comb is recommended to help remove dirt and other debris. If you can’t find a fin comb, a cloth with water is sufficient. Just be careful.

Give your window AC unit an hour or two to dry before plugging it in and starting it again. If it’s hot out, placing a standing fan in front of your window AC unit or opening a window can help speed things up.

If cleaning your window AC unit was due to an issue (mold or mildew smell or underperformance), see how it works after you start it up again.

Modern devices are designed to last eight to 10 years, and many of them come with a warranty of at least five. With regular maintenance and filter cleanings, though, you could easily double the life of your device.

A local HVAC repair specialist can diagnose your device and decide if it’s time to get a new one.