How To Clean a Window AC Filter

Place air conditioner in a serviceable spot

• Retrieve your window air conditioner from storage. Depending on the size and weight, you may need someone to help you lift it.
• Place your AC on a flat, clean surface of convenient height for cleaning, like a deck. It’s also possible to clean the filter after installing the unit in a ground-level window, provided you can easily reach the window and the AC.
• Orient your AC unit so you can access the air filter. It’s usually on the side with the controls.

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Open cover and remove air filter

• Examine the front edges of your AC unit for notches that allow removal of the plastic cover.
• Remove the cover carefully and place it to one side. The air filter should now be visible.
• Slide the filter out of its housing notches, then place it to one side on your work surface.

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Vacuum air filter and AC unit

• Use a shop vacuum to remove dust and lint from both sides of the air filter. I get better results using the vacuum hose without any brush attachments.
• Place the vacuumed filter down on your work surface. Then, carefully vacuum all visible inside surfaces of the AC unit, including the slats of the outer plastic cover.
• Take care not to damage the fins or tubes inside your AC.

Robert Maxwell For family handyman

Wash air filter

First, use dish soap

• Fill a bucket with warm, soapy water. (Dish soap works well.)
• Gently scrub all parts of the air filter, back and front, with an old toothbrush, dipped in soapy water.
• Go over the filter multiple times to remove all traces of dust and dirt.
• Rinse the filter with a hose or outside tap.

Then, use vinegar

• After cleaning it with soapy water, if the filter has a musty smell or visible mold, Justin Cornforth, HVAC technician and owner of Ace Home Co, recommends soaking it in a solution of one part vinegar to three parts water for 15 minutes.
• “Scrub lightly to remove mold, then rinse thoroughly with clean water, and let it sit in a sunny spot to dry completely,” Cornforth says.

Robert Maxwell For family handyman

Clean evaporator coils

• Use a soft brush to clean the evaporator coils placed behind the filter and condenser coils at the back of the unit. “Dirty filters do not filter air properly, and some dust and debris can accumulate on the coils.”

Wipe down the AC filter

• Vacuum or wipe the filter slot before putting the filter back in. “Even if the filter is thoroughly cleaned, dust and debris in the slot can undo all your hard work, contaminating the clean filter,” Cornforth says.

Replace air filter

• Once the air filter dries fully, slide it back into its housing notches inside your AC unit.
• Replace the outer plastic cover, double-checking to ensure it’s properly latched.

Check the fit

• Check the filter’s fit when sliding it back into the unit. “If it’s not snug or has gaps around the edges, dust and debris can bypass it and get into the internal parts of your AC unit,” Cornforth adds.

FAQ

How often should you clean your AC filter?

In general, you should clean your AC filter at least once a month, and now that you know how to clean it, it shouldn’t be too difficult. “Once a month is recommended, but the need can change depending on environment, run time, indoor air quality,” says Jeff Ault, virtual HVAC technician for Frontdoor. “Cleaning the filter helps with both efficiency of the unit so it can cool properly as well as keeping the internal components of your AC unit clean.”

When is it time to replace my AC filter?

It is time to replace the air conditioner filter (as opposed to cleaning it) when the membrane gets damaged. “The membrane, or an ‘air filter membrane’ in a window AC unit is the thin, often paper or fiberglass material that acts as the primary filtering component within the AC, capturing dust, pollen, pet dander, and other airborne particles before they circulate through the room.

“It’s the barrier that prevents debris from entering your home through the air conditioner and the part of the filter itself that needs to be regularly cleaned or replaced to maintain optimal air quality,” Ault says. “These filters could break from normal wear and tear over a long period of time or damage could result from scrubbing it too hard, simply mishandling or being too rough when removing or installing the filter.”

About The Experts

• Justin Cornforth is the owner of Ace Home Co, a family-owned HVAC and plumbing company founded in 2017. A leader of the company, a former technician, and a frequently published expert, Justin knows everything about home heating, cooling, and plumbing, and loves sharing his expertise to help homeowners address their problems.
• Jeff Ault is a virtual HVAC technician for Frontdoor who is currently licensed in the state of Arizona. With 14 years of experience in the HVAC trade, one of Jeff’s greatest values has always been honesty. He understands that home repair can be daunting and expensive, and he seeks to ease that burden by providing peace of mind and transparency.