How to Clean Window Air Conditioner Mold

Last updated on November 9, 2023

Does your window air conditioner have a mold build-up? You need to clean that as soon as possible. Here’s how to do it right.

Mold is one of the last things that any homeowner wants to deal with, but it still remains to be one of the most common problems we face within our homes today. 

According to the CDC, mold “will grow in places with a lot of moisture, such as around leaks in roofs, windows, or pipes, or where there has been flooding. Mold grows well on paper products, cardboard, ceiling tiles, and wood products. Mold can also grow in dust, paints, wallpaper, insulation, drywall, carpet, fabric, and upholstery.” 

In other words, it can grow just about anywhere, and since the interior of a window AC unit is often dark, warm, and moist, this is the perfect breeding ground for mold to flourish. And it isn’t doesn’t just leave a nasty odor, but it can also lead to some serious health problems. 

The good news is that there are ways to prevent it from forming in your window AC unit (tips on that later), but what should you do if your AC is already riddled with mold? 

The Cleaning Process: How to Get Rid of Mold

ac mold

Getting rid of mold in a window air conditioner is as simple as giving the unit a deep clean, but there are very specific steps that you need to follow in order to stay safe. If you suspect mold, always turn off the unit immediately to prevent spores from spreading throughout the home. 

  • Before you get started, here’s what you’ll need to organize: 
  • Protective gear (gloves, mask, goggles)
  • Screwdriver
  • Wet/dry vacuum with a nozzle attachment
  • Commercial AC coil cleaner
  • Garden hose
  • Dish soap
  • Bleach
  • Large plastic bucket
  • Scrubbing sponge

Once you’ve gathered all the necessary supplies and have your protective gear on, remove the unit from the window (you’ll need a screwdriver for this). Be careful, even small window AC units are heavy, so this will probably require two people. Once removed from the window, take the unit directly outside. 

Every window unit has a grille located at the front – remove this. This will give you easy access to the filter, which also needs to be removed. Soak the filter in hot soapy water that contains about ½ cup of bleach. Then, following your owner’s manual, remove the top and back of the unit’s cabinet. 

Using the wet/dry vac, vacuum out any dust and debris that has built up inside the unit over time. You’ll see a few U-shaped metal tubes near the front and back of the unit (called coils) – spray these down with commercial coil cleaner (you can find this at any hardware store). 

A commercial-grade coil cleaner is capable of dissolving just about anything, including mold. Read the instructions on the label to determine how long to let the cleaner sit. Once you’ve waited the recommended amount of time, spray the coils down with a hose to wash away the solution. Avoid getting the controls and electrical cord entry wet. 

Take your plastic bucket and fill it with a hot water/bleach solution (once again, ½ cup bleach should do the trick). Make sure you have gloves on for this step. Next, saturate a scrubbing sponge with the water/bleach solution and give the inside of the unit a complete wipe-down. The bleach is the key ingredient in killing any remaining mold spores.

The filter should still be soaking in water, so now it’s time to remove it. Spray it down with the hose to remove any residual soap suds and lay it on a clean surface to dry. Allow the entire unit to dry (this usually takes a full day) before replacing the filter and reinstalling it in the window. 

3 Window AC Mold Prevention Tips

window ac unit

Now that you know how to clean mold after it has formed in the AC, it’s up to you to prevent it from happening in the future. Luckily, there are some easy steps you can take so that you never have to clean mold from your window unit again. 

Select a Unit With a Humidity Control Feature

If you already have your window unit, this first tip won’t help you out too much. But if you are in the market for a brand new unit, choose one that features humidity control. Since mold is caused by an excess of moisture, it goes without saying that controlling the humidity is a solid prevention tactic. 

Use Auto Mode Whenever You Can

Your unit’s Auto mode is there for a reason, so use it. This setting means that the AC is never fully off, which might sound inefficient, but it can actually help to keep your home’s climate stable. But better yet, it’s a great mold prevention tool. 

When an AC sits unused for an extended period of time, mold is much more likely to form due to a buildup of moisture, stagnant air, and other factors. But with the Auto function turned on, the continuous cycle of airflow can keep mold from forming inside the unit. 

Keep Up With Regular Maintenance

This is something you should be doing anyway to keep the unit running smoothly. But regular maintenance also helps you to detect problems that could, later on, lead to the formation of mold. It also allows you to catch mold early on before it completely takes over. 

Many people are unaware that dust and mold go hand in hand, and dust can actually promote mold growth. Do your best to get rid of the dust on and inside your unit as often as you can.  

A Final Note on Mold in Your Air Conditioning Unit

ac maintenance

Not only do you now know how to eradicate mold from your window unit, but you also know how to prevent it from forming in the first place. 

Safely removing mold from your window unit is a relatively easy process, but always remember that mold isn’t something to mess around with, so if the unit has reached a point of no return, the best option is to buy a new one. 

Happy cleaning!


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