How to Clean a Window AC Unit to Keep It Running Smoothly All Summer Long

Remove dust, debris, and mildew from your air conditioner in just a few simple steps.

Throughout the warm summer months, your air conditioning keeps you and your loved ones cool and comfortable. But if it's been a while since you cleaned your window air conditioner, it's time to give your AC a little TLC. Consistently cleaning a window AC unit not only allows it to operate efficiently and use less energy, but it also prevents unwanted mold and mildew, which can have adverse health effects, from forming and growing inside of your unit.

With a few common household materials and this easy step-by-step guide, you can care for your window AC and make sure it's ready and able to keep you cool during the hottest months of the year and beyond.

removing filter from window air conditioner unit
Courtesy of Walmart

How to Clean a Window AC Unit

Don't let dust and debris build up in your window air conditioner. Follow our step-by-step instructions for cleaning an AC unit to keep it performing its best.

What You'll Need

  • Screwdriver (optional)
  • Hand vacuum or vacuum with hand attachment
  • Bucket of warm water
  • Soap or detergent
  • Bristle brush
  • Toothbrush
  • Can of compressed air
  • Cleaning rag or cloth
  • Spray bottle
  • Hydrogen peroxide (3%)

Step 1: Clean the air filter.

Before cleaning your air conditioner, ensure that it is unplugged from the power source. Next, locate and remove the filter on your AC unit. Some window units feature filters that simply pull out; others might first require the removal of the front cover with a screwdriver. Look at the manufacturer's manual for your model to determine the best method for removing your AC unit's filter.

After removing the filter, use a hand vacuum to extract as much dust and debris as possible. Next, grab a bucket with soapy water and a bristle brush and wash the filter in the sudsy water, gently brushing it as needed until clean. Air-dry the filter completely before re-installing it.

Step 2: Clean air-conditioner coils and fins.

Locate the evaporator coils and fins in your unit, which convert hot air into cool air, and clean them using a toothbrush or other soft-bristle brush. Be gentle and handle the coils and fins with care so as not to bend or damage them. Spray the coils and fins with compressed air to remove any remaining dirt and dust.

Step 3: Clean the exterior and grill.

Clean the grill of your air conditioner with a damp cloth or rag. If the grime is substantial, remove the grill according to the manufacturer's instructions and submerge it in warm soapy water, using a brush or rag to clean between the grill's gaps. Dry the grill completely before reinstalling it.

Next, wipe down the top and sides of the window AC unit with a damp cloth. If your AC has a drain and/or drip tray, be sure to clean those as well by emptying them and wiping them clean. Let dry completely before returning to the AC unit.

Step 4: Prevent mildew and reassemble.

Using hydrogen peroxide in a spray bottle, treat the exterior areas of the air conditioner where air flows through to protect against mold and mildew. Allow enough time for all parts to dry completely before putting them back in place. Now, all that's left to do is kick back, relax, and enjoy your clean AC unit as it blows fresh, cool air into your home.

How Often Should I Clean My Window Air Conditioner?

While there are several components of your window AC unit that require attention on a regular basis, the most critical piece to clean routinely is the filter. It is recommended that you wash the removable filter once a month. Depending on how frequently you operate your AC, your window AC filter might also eventually need to be replaced. Many units have a light that comes on to indicate when it is time to replace the filter, so you'll know exactly when to swap it out for a new one.

During months when your window AC unit is not in use, you can choose to remove and store it or invest in a window cover for off-season protection. Both options option will lessen the amount of dirt and debris that makes its way into and onto the unit.

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