Convinced There’s Mold in Your Window Air Conditioner? Take Your AC Apart.

It had never crossed your mind that mold can grow inside an air conditioner, but since Midea’s recall of 1.7 million U and U+ window air conditioning units due to risk of mold exposure a few days ago, you’ve been side-eyeing your own window AC like it’s a petri dish for airborne Cordyceps. What can you do now to make sure once and for all that the air you’re blowing onto your furniture, food—your kids—isn’t full of mold?

Getting mold out of an air conditioner depends on where the mold is in the unit. If you can get to the mold, you may well be able to remove it yourself—so let’s take that baby apart! The bad news is, if the mold is growing in a section of the unit that’s difficult to access, you’ll either need to hire an HVAC professional to clean it or replace the AC entirely. Let’s get to it: Here’s what to do so you can stop having nightmares about The Last of Us and get some sleep again.

1. Turn off the air conditioner.

If you suspect there’s mold inside your AC unit, the U.S. Environmental Protection Agency recommends unplugging and turning off the unit so no more mold spores can circulate and contaminate your home. Turning off the unit also allows you to test the unit for mold to determine what types of spores you’re dealing with.

2. Inspect the unit with a flashlight.

• Remove the air conditioner’s front grille cover (most snap off but some are held in place by screws), and then pull out the filter beneath the grill.
• With a flashlight, inspect the inside of the unit for the signs of mold growth, which may appear as streaks or clusters of brown, black, or greenish stains, some of which may appear fuzzy. Mildew, a common type of mold, produces powdery gray or white stains.
  • If you find just a few traces of mold on the hard surfaces inside the unit, proceed with cleaning.
  • If it’s filled with heavy mold growth, indicated by mold and mildew deposits that cover one-third or more of the surface area of the case and the internal workings, it’s probably time to replace the unit.
• If you suspect mold, conduct a DIY test with a mold test kits or contact a mold removal company.
• If the unit is visibly overrun with mold, skip to number 4.

3. Remove the air conditioner from the window and clean it.

Air conditioning units vary in the way they are assembled, so check your owner’s manual to determine how to identify and disassemble the exterior cabinet so that you can access the interior. The manual may also contain instructions on how to clean an air conditioner that are specific to your model, but the general procedure goes like this:

• Remove the unit from the window, using a screwdriver to remove the frame that secures it. AC units are heavy, so ask someone to help you remove it and place it on a concrete surface or on a large piece of plywood.
• Remove the grille and the filter from the front of the unit. Soak the filter soak in a sink with hot soapy water to which you’ve added approximately 1/2 cup of bleach.
• Remove the top and the back of the cabinet, following the directions in your owner’s manual.
• Vacuum out dust and debris from the inside of the air conditioner. Use a nozzle attachment to get out as much as possible.
• Spray the coils (U-shaped metal tubes near the front and the back of the unit) with commercial coil cleaner and let the product dwell as directed by the manufacturer to dissolve anything that’s collected on AC coils. Cleaning the debris on the coils is crucial because it provides a breeding ground for mold.
• Spray the coils with a garden hose to remove the coil cleaner solution. It will have dissolved the gunk and it should spray right off. While window AC units are fairly waterproof, avoid spraying the controls and the spot where the electrical cord is attached.
• Fill a plastic bucket with a few gallons of hot water and about 1/2 cup of household bleach.
• Saturate a scrubbing sponge in the bleach solution and use it to wipe the inside surfaces of the AC unit, removing all traces of visible mold. The bleach will kill residual mold spores.
• Spray the filter that’s been soaking in the sink with the hose to remove all debris.
• Allow the unit to air-dry completely, which could take up to 24 hours, before reassembling the unit and reinstalling it in your window.

Pro Tip

Once you’ve had mold in the air conditioner unit, there’s an increased risk that it will develop again despite your cleaning efforts. This is because mold spores could remain within the inner workings of the unit that you were unable to reach. The presence of dust in the unit helps mold spores adhere and grow, so make it a practice to remove the grille and filter every few weeks and vacuum the interior of the unit to keep dust from settling and get rid of any dust that has accumulated.

4. If the air conditioner is overrun with mold, replace it.

If upon your initial inspection, you discover rampant mold and mildew in the air conditioner, do not attempt to clean it. Visible heavy mold indicates that more mold is flourishing in places you cannot see or easily reach, such as within the fan motor casing. You could call a mold remediation specialist to inspect the unit to see if it can be professionally cleaned, but the consultation could cost as much as purchasing a new air conditioner.

For top-notch alternatives to Midea’s recalled air conditioners, consult our tested guide to the best U-shaped air conditioners.

 

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