How to Clean an Air Conditioner With Mold: A Step-by-Step Guide

Breathe easier by cleaning your air conditioning unit in 10 quick steps

mom and baby playing on couch
Photo: Monkey Business / Adobe Stock
mom and baby playing on couch
Photo: Monkey Business / Adobe Stock
SKILL LEVEL
Intermediate
COMPLETION TIME
2 hours
COST
$25
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What you'll need:
TOOLS
  • Face mask
  • Protective eyewear
  • Latex gloves
  • Screwdriver
  • Vacuum
SUPPLIES
  • Water
  • Disinfectant

If you’ve spotted signs of mold in your AC unit or ductwork (for example, musty smells or fuzzy patches), it’s time to break out the cleaning supplies and learn how to clean an air conditioner with mold. With a bit of elbow grease and some mold-killing agents, you should be able to remedy the situation. And while motivated DIYers can remove most AC mold, severe or hard-to-reach cases warrant the help of an HVAC professional.

  1. Turn Off Your Air Conditioner

    stylish living room with ac on wall
    Photo: Pixel-Shot / Adobe Stock

    Avoid spreading more unhealthy air by powering off your central air conditioner. A contaminated AC can circulate mold spores throughout your home.

  2. Put on Protective Gear

    Protect yourself from potentially dangerous mold by donning protective eyewear, non-porous gloves, and a face mask. If you don’t have any of this equipment, you can find it all at your local hardware store.

    Mold exposure can make you sick. If you’re concerned about its health effects, consider hiring an HVAC professional or mold remediation specialist to do the dirty work for you.

  3. Inspect for Mold

    Take a look at your central air conditioner to determine the extent of the mold problem. You may see visible dark spots or white fuzzy growths, which are indicators of a mold issue. But even if you can’t see any mold with your naked eye, it can still be a problem. If you notice a not-so-fresh smell when you turn on your air, there could be some kind of contamination in your unit.

    Grab a flashlight and look inside the unit for signs of mold. If you see heavy mold growth that covers half or more of the unit’s surface area, call a professional for AC mold removal. You can clean smaller deposits yourself.

  4. Mix Cleaning Solution

    In a bucket, mix a cleaning solution that will kill the mold growing in your unit. Most household multi-purpose cleaners will do the trick, but you can also use distilled white vinegar.

    You may also choose to purchase 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.

  5. Remove Air Conditioner Components

    If you’re working with a window AC unit or individual vents, use a screwdriver to remove the grille from the front of the unit. Continue removing the top and back of the cabinet as well as the front filter. Find specific directions for how to do this in your owner’s manual.

  6. Vacuum Inside Air Conditioner

    Remove dust and debris from your AC with a vacuum. Use its various attachments and hoses to get into every nook and cranny. This will make further clean up a bit easier.

  7. Scrub Inside Air Conditioner

    Dip your scrubber in your mixture of AC mold cleaning solution and warm water and thoroughly scrub the mold in and around your AC unit. If the mold isn’t well-established yet, you will likely be able to wipe it away with little effort. Call a professional to remove the mold if it’s persistent.

  8. Rinse

    Allow your cleaning solution to sit on the central air conditioner for about 10 minutes before spraying it with clean water and wiping it with a clean cloth.

  9. Allow AC Unit to Air Dry

    Allow the unit, filter, grille, and cover to dry completely before turning your air conditioning back on. This could take up to 24 hours, so seek out other room cooling methods if you have to clean your unit on a sweltering summer day.

  10. Re-Install AC Components

    Once everything is completely dry, you can put the pieces back on your unit and turn it back on. If you notice a bad smell or feel sudden allergy symptoms, there’s likely still mold in your unit. If that’s the case, call a mold removal specialist in your area for help.

Why Does Mold Grow in an Air Conditioner?

There are several reasons mold can grow in an air conditioner. The main attraction for mold is moisture, and ACs have plenty of that since they work by removing moisture from the air. If your AC's condensate drain is clogged and water backs up in the unit, mold can thrive. 

Mold can also grow in your AC if you don't clean it regularly and it becomes clogged with dust, dirt, pollen, and dead skin cells—all organic matter that mold feeds on. Add to that a steady temperature of between 60 and 80 degrees Fahrenheit and high humidity levels in your home, and you've got optimal conditions for AC mold growth.

Cost to DIY Mold Removal in an AC Unit vs. Hire a Pro

If there isn’t a significant amount of mold in your air conditioner, you may decide to DIY this project. In that case, you’ll only need to pay for materials. It will cost you less than $50 at your local home improvement store to purchase must-have cleaning supplies and protective gear. 

Professional mold treatment costs between $3,000 and $10,000. Professionals will have special tools to completely remove all mold and airborne spores. Hiring a professional to remove your mold is a great choice for people who are sensitive to mold—cleaning it yourself could make you sick. 

If your contaminated A/C or HVAC system is full of hard-to-reach areas that you can’t clean, call a local HVAC company for help. Consider mold remediation an investment in your family’s health. If the mold in your air conditioner isn’t widespread, you can likely remove it yourself with an at-home AC mold cleaner.

Angi Tip

Do not mix vinegar with hydrogen peroxide or bleach. Mixing vinegar with hydrogen peroxide creates a toxic chemical that can irritate your skin and eyes. Combining vinegar and bleach can create a toxic chlorine gas.

Caroline Gilbert
Director, Content & Editorial, Angi

How to Prevent Mold in Your AC Unit

Reducing moisture and promoting proper airflow are the keys to preventing mold from growing in your air conditioner. Here are some ways to do that: 

  • Change the filter regularly: As your air conditioner runs, the filter fills up with dirt, dust, and other debris. Replacing your AC filter regularly (every one to three months) can prevent mold from growing in the filter and spreading to other parts of your HVAC system.

  • Clean the air intake and AC registers: Getting rid of debris and condensation around your home’s air intake and registers helps air flow freely through your ductwork, making mold less likely to grow.

  • Schedule a professional inspection: During an inspection, your HVAC technician will deal with mold problems and clean your entire AC system. This helps it run more efficiently, potentially saving you money on energy costs. A yearly inspection can also uncover minor issues before they turn into expensive problems that need to be addressed by a local AC repair company.

Frequently Asked Questions

You should not run an air conditioner with mold because it could spread the spores throughout your home. Mold exposure can trigger several health problems, including coughing, wheezing, sneezing, itchy eyes, and a sore throat. Living in a moldy house can also increase your risk of other illnesses, including sinus infections, pneumonia, and bronchitis.

It depends on the type of AC unit and the extent of the mold growth. For example, if you have a small amount of mold in your central air conditioner, it’s worth cleaning it to protect your HVAC system and your health. In situations like these, you can often remove the mold yourself in a couple of hours. On the other hand, if you have a portable AC unit with a severe mold problem, it makes more sense to buy a new one. On average, replacing a portable AC unit costs $100 to $500.

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