How to Clean Mold Out of Your Air Conditioner (2024 Guide)

By Jesus Sanchez Garcia Updated February 5, 2024

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Even the best air conditioners are prime targets for mold. Organic matter from airborne particles can build up in the air filter, and the surrounding warm, moist air creates the perfect environment for mold growth. This is scary considering all the air you breathe in your home is filtered through your AC. 

Mold in your AC poses a significant health risk and can spread throughout your home if left untreated. Follow our step-by-step guide to remove it.

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Common Signs of Mold in Your Air Conditioner

Before cleaning out your AC, make sure you’re dealing with mold. The most noticeable sign is a musty scent that only seems to fill the room when you run the AC. Be aware that the smell might be limited to a single room if you’re using a window-mounted or wall-mounted AC. The scent can fully permeate your home if you have a central AC unit.

The other sign to look out for is large mold patches around your AC unit. If you notice fuzzy, black, or greenish black patches, that’s mold. Mold can also be brown, white, pink, yellow, or orange, but greenish black is the most common color.

Another way to check if your wall-mounted or window air conditioner has mold is to unplug the unit and remove the front or back grill to access the filter. Pull the filter out and visually inspect it for black or green stains. If the filter doesn’t show any signs of mold but you still smell something musty, grab a flashlight and inspect the inside of the unit. Mildew can also produce a powdery gray or white stain.

If you have a central AC unit, you can use a flashlight to inspect the supply vents, ductwork, fan, and exterior air conditioning unit for signs of mold buildup. However, since most of the unit is inaccessible, you’ll need to hire a professional HVAC technician for a more thorough inspection.



How to Clean Mold Out of Your Air Conditioner

Once you’ve confirmed mold is the problem, prepare to clean out your AC with the following tools and supplies: 

Next, follow these simple steps to clean your AC unit and remove mold

  1. Turn off the air conditioner: Ensure you turn off the unit for your safety and to avoid spreading more unhealthy air. If contaminated, the AC unit will circulate mold spores throughout your entire home.
  2. Protect yourself: Mold exposure can make you sick, so ensure you have protective gear before getting started. We recommend eyewear, gloves, and a face mask. If you’re concerned about health effects, call a professional to do the dirty work for you.
  3. Make the cleaning solution: Mix a cleaning solution that will kill the mold in a bucket. You can use diluted bleach or distilled white vinegar, or you can buy an Environmental Protection Agency-registered mold removal solution from your local hardware store. Aim for a 1:3 ratio of cleaning solution and warm water.
  4. Take apart the AC unit: Use a screwdriver to remove the grille from the front of the unit. Then, remove the top and back of the cabinet and the front filter. Check for specific directions in the unit’s owner’s manual if you get confused. 
  5. Vacuum the inside of the AC: Before applying the cleaning solution, get rid of dust and debris with a vacuum. We suggest using various attachments and hoses to get into every tight corner. This makes cleanup easier.
  6. Scrub the inside of the AC: Dip the scrub brush in your cleaning mixture and warm water. Then, scrub the mold in and around your AC unit. If the mold isn’t well-established, you can probably wipe it away with little effort. If the mold remains despite your best effort, call a pro.
  7. Rinse the AC unit: Once you’ve allowed the cleaning solution to sit on the air conditioner for about 10 minutes, spray it with clean water, and wipe it with a clean cloth.
  8. Reinstall the AC unit: Once everything is dry, you can put back together your unit and turn it on. If you notice a terrible smell or experience sudden symptoms, there’s likely still mold in your unit. Call a specialist for help if that’s the case.



How to Prevent Future Mold Growth

Now that your air conditioner unit is working again, it’s important to prevent future mold growth. Here are some simple, precautionary steps you can take.



When to Contact a Professional

The average homeowner can easily remove mold from a wall-mounted or window AC unit. You should contact a pro if you’re unable to remove the mold after giving it your best effort, or if you simply don’t want to deal with the hassle or potential health risks. It’s best to contact a professional for mold remediation on any central air conditioning system. Trained professionals can access all parts of the system and treat the problem without damaging the unit, air ducts, or vents.



Our Recommendation

Cleaning mold out of a wall-mounted or window AC unit is relatively easy if you follow the steps in this article. We recommend contacting a professional if you have central AC, since these systems are more complicated and difficult to access. Hiring a professional ensures your mold problem will be addressed effectively. A technician can also provide tips for preventing future mold.

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How to Clean Mold Out of Your Air Conditioner FAQ

Is it safe to run an air conditioner with mold?

No, it is not safe to run your air conditioner if it has mold, as this will spread it to your air ducts. Black mold is especially dangerous, so it’s important to remove it quickly.

Can I spray Lysol in my AC unit?

Do not use Lysol to clean your AC or combat mold in the AC. Lysol has a high concentration of ethanol alcohol, which makes it highly flammable. 

What does AC mold smell like?

When your AC has mold, you’ll notice a powerful ammonia odor or musty smell circulating in your home.