How to Clean Your Window AC Unit in 8 Simple Steps

Say goodbye to dust, dirt, and more

Ben Kissam
Written by Ben Kissam
Updated June 20, 2022
woman relax in chair at desk at home
Photo: fizkes / Adobe Stock


Perfect for handy homeowners.

Time to complete

45 minutes



Just a short shopping trip (or online order)

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What you'll need:


  • Spray bottle
  • Bucket
  • Rubber gloves
  • Vacuum with hose extension
  • Fin comb


  • Coil cleaning solution
  • Soft cloth or paper towels
  • Optional: Replacement filter

Whether there’s a mildew scent coming from your window air conditioner or you just feel like it’s not working like it’s supposed to, cleaning your device is a solution that can fix many problems.

In fact, regular cleanings will help ensure the air in your home stays clean, and that your device stays as energy-efficient as possible. Here’s how to clean your window AC unit in eight simple steps.

  1. Gather Cleaning Materials

    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.

  2. Disconnect Your AC From Its Power Source

    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.

  3. Clean the Outside Cover

    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.

  4. Remove and Clean the Filter

    Outdoor window air conditioning units
    Photo: James / Adobe Stock

    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.

  5. Vacuum Your Unit

    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.

  6. Use a Comb to Straighten the Fins

    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.

  7. Let Your Window AC Unit Dry

    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.

  8. Assess

    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.

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Get quotes from top-rated pros.