How To Thoroughly Eliminate Mold and Musty Odor From Car AC

Josh Mitchell

Written By

Josh Mitchell

Expert Reviewed By

Holly Curell

Last Updated On

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As soon as I detected mold in my car's AC system, I was tempted to sell my Hyundai Kona just so I wouldn't have to deal with the problem.

After a lot of research and testing different mold cleaner products, I can now breathe mold-free air while behind the wheel.

In this complete guide, I’ll cover all the steps for how to get rid of mold in car air conditioner systems, as well as provide helpful mold prevention tips to keep your air conditioning system free of this harmful fungi.

Key Takeaways

  • To get rid of mold in car AC, you will need to dry your car out, clean the vents, plenum and the evaporator with disinfectant sprays and also perform a thoroughly cleaning indoor.
  • The tell-tale signs of mold include musty and mildew smell, blocked air vents and noticeable health effects such as sneezing, irritation or coughing.
  • Do not run your car AC if there is mold present or if you suspect mold growth.

DIY Guide To Getting Rid Of Mold And Musty Smell

Mold thrives in damp, dark environments.

Unfortunately, the internal mechanisms of an air conditioning system are dark and, in some cases, damp.

Whether from simple humidity issues or a manufacturer defect, it's important to act fast when it comes to mold growth.

Luckily, I detected my car’s mold issue immediately, all thanks to the musty odor and the fact that my AC started to blow moist air.

Later, I’ll cover more tell-tale signs that mold is present in your vehicle, but for now, let’s focus on how to get rid of mold in car air conditioner systems.

How to get rid molds

Tools You Will Need To Get Started

Before you can eliminate mold from your car air conditioner, you'll need a few things.

  • Protective gear, like eye goggles and gloves[1]
  • Antibacterial mold cleaning solution
  • Cleaning brush and/or towels
  • New car air filter

Important Note:

While you may be tempted to skip the protective gear, you’ll be putting your health at risk if you do.

Most people experience minor reactions to mold, like itchiness or mild eye irritation, but those with an allergy or other underlying health issues can show some serious symptoms.

Step 1: Dry Out The Entire Vehicle

Mold can only thrive where moisture is present, so drying out the entire vehicle and ridding it of moisture is step 1.

Before you can even get started with the mold disinfectant, it’s important to ensure that the vehicle is dry and moisture-free.

There are a few ways to make this happen. If you live in a hot, arid climate, simply park your car outside in direct sunlight and roll the windows open.

(This obviously won't work if it's a rainy day or if you live in an area with high humidity levels.)

If that applies to you, it’s time to invest in a portable dehumidifier. I own a small dehumidifier that’s specifically designed for use in my car, and it works wonders!

Any time I need to remove moisture from my car, I simply turn on the device with the doors closed and windows rolled up.

You can also use a small fan to complete the drying process or even a heavy-duty leaf blower.

TL;DR: To dry the car out, use the heat of the sun or even consider investing in a dehumidifier.

Step 2: Remove Excess Debris, Dirt & Dust

Now that your car is dry, the next step is to do a quick clean to remove any excess dirt, debris, dust, and mystery items that have been under your passenger seat for God knows how long.

During this step, I found an old fuzzy French fry from McDonald's!

This is the perfect time to spot-clean your car. If the mold spores have spread to the upholstery and fabric, it's necessary to clean these so that the mold disinfectant can penetrate the fabric more effectively.

I prefer to do this by vacuuming with my cordless Dyson after charging it up.

If you don’t have a vacuum that will work in the car, head to your nearest carwash and use the vacuum station.

TL;DR: After drying, clean the car out thoroughly. Check every nook and cranny indoor for dirt, debris and left-overs.

Step 3: Spray The Mold Cleaner On The Evaporator

Since you know that the source of the mold is within the air conditioner, it’s important to start by disinfecting the evaporator.

This component is responsible for the heat exchange necessary for the AC to function.

As hot outdoor air is pulled through the AC's air intake, it cools down as it passes through the evaporator and transfers heat to the refrigerant.

Accessing the cooling evaporator is pretty simple. It’s usually inside a molded plastic casing located behind the glove compartment.

In some cases, you’ll have to remove the entire front panel to access it, so refer to the instructions in your car’s user manual.

Once you’ve made a clear path to the evaporator system, grab your mold-cleaning spray.

There are tons of different products on the market that are safe to use on the internal mechanisms of the AC.

My favorite product for this step is the DWD2 Clean Air Spray, which is specifically designed for evaporator cleaning.

Simply spray the solution into the vents, and it will make its way to the evaporator. There's no need to remove the car's instrument panel!

TL;DR: Access the evaporator and use a disinfectant on it. Getting to the evaporator can get tricky. 

Step 4: Spray The Mold Cleaner Into The Plenum

In automobile HVAC, a plenum is a part of the system used as an air intake for the AC during fresh air mode operation.

It's typically located between the front windshield and the hood of the car.

Because fresh air passes directly through the plenum, ridding this component of mold is the only way to solve your problem for good.

You can use any mold control cleaner for this step, but it's best to find one specific for cars.

TL;DR: Make sure you pay particular attention to cleaning the plenum.

Step 5: Disinfect And Wash The Interior

Even though the source of the mold is within the AC, it’s very likely that spores have spread to other areas of the car’s interior.

Fabric upholstery, like seats and floor rugs, is especially susceptible to mold, so focus on these in this step to rid your car of mold.

There are several options for liquid cleaning solutions. If you prefer an all-natural cleaner that’s non-toxic as well as inexpensive, I recommend using white vinegar.

You can make a homemade solution by combining 4 parts vinegar with 2 parts water.

Another option is to use a dedicated mold spray, like the Lysol Mold & Mildew Remover or the Mold Armor Mold Kill & Control.

These are both super affordable as well as effective. All you have to do is spray the interior surfaces, wait a few minutes, and wipe it clean.

I personally like using an extractor that allows you to distribute the solution while simultaneously scrubbing it into the material.

For this step, I used a homemade vinegar solution with my Bissel Little Green machine, and it worked wonders!

ACLAB Note:

Just avoid using anything with hydrogen peroxide since this can bleach the fabric.

If the mold spores have left stains throughout your car’s interior, I suggest using Borax powder.

TL;DR: Thoroughly clean the interior either with disinfectant chemical or by creating a home made solution of water and vinegar. 

Step 6: Replace The Air Filter

Lastly, it's a good idea to install a new cabin air filter. The old one is most likely riddled with mold, so it's definitely time to get rid of that.

Even if you don't see any dangerous mold on the filter, it's recommended that drivers replace this filter between every 15K and 30K miles.

Luckily, a new filter will only set you back about $10. Just be sure to purchase one that’s compatible with your car’s make and model.

TL;DR: Get rid of your old air filter and replace it with a new one even if you don't see visible signs of mold on it.


What Causes Mold Growth In A Car’s AC?

According to the EPA, “Molds are a natural part of the environment and can be found almost anywhere that moisture and oxygen are present…There are many types of mold – all of them need water or moisture to grow.”[2]

By that definition alone, it’s clear that mold only thrives where moisture is present, and when left untreated, the spores colonize and spread.

The presence of moisture in your vehicle’s air conditioning can be caused by many things, including:

  • Condensation on the AC heater core
  • Spilled liquids within the vehicle, especially on fabric and upholstery
  • Lack of airflow from the air conditioning system (not using the AC enough)
  • Moisture within the cabin filter
  • High humidity levels based on your geographic location

TL;DR: Any part of your car that can get damp and dark, it will lead to mold growth.

Signs Of Mold Growth In Your Vehicle

When mold invades homes and buildings, it's often visible and easy to spot.

However, when mold takes over a vehicle, the spores can be hidden away within air ducts, in the vent system, and even in between seat cushions.

Because it’s not always detectable to the naked eye, it’s important to consider other signs that mold has taken over your car’s air conditioning system.

Here are a few indicators that mold is present in your vehicle:

  • Your Car AC Smells Like Mold:
    If your car actually smells like mold or mildew, it’s very likely that mold is growing within the air conditioner. As mold spreads, it emits gases known as microbial volatile organic compounds, MVOCs for short. These gases have an unpleasant odor, similar to what you’d smell when walking into a dark, damp basement.
  • Your Car's Air Vents Are Blocked:
    The vents that expel hot and cold air can easily get blocked by dirt, debris, dust, and, worst of all, mold. If you've noticed that the AC system in your vehicle is struggling to blow air, it could be due to mold overgrowth.
  • You’re Experiencing Mold-Related Symptoms While Driving:
    Exposure to mold can have a wide range of negative side effects, like sneezing, congestion, itchiness, wheezing, watery eyes, and even fatigue. If you’re experiencing any of these symptoms while in the car, it can probably be explained by mold spores blowing from the air conditioner.[3]

TL;DR: The most noticeable sign is musty smell. If this is either accompanied with blocked air vents or negative effects to your health then you most certainly have mold growth.


Tips On How To Prevent Mold Regrowth

Now that you’ve taken the steps to eliminate mold from your car, it’s still important to do what you can to prevent mold growth from happening again.

How to prevent molds

Here are a few tips for preventing mold from taking over your vehicle:

  • Keep your car clean and dry. If you spill any liquids, dry everything out thoroughly.
  • Regularly clean and shampoo car seats, upholstery, and other fabrics within the vehicle. After cleaning, dry everything out by opening the windows or keeping the car running with the air on full blast.
  • Invest in a car dehumidifier if necessary. You can easily find these handy little devices on Amazon for less than $20.
  • Invest in seat covers to protect your car’s upholstery. Seat covers are easy to remove and clean if any liquids are spilled.
  • Invest in rubber floor mats. Floor mats are great for catching any spilled liquids and keeping moisture from setting into the fabric floor mats that come with most cars and trucks.

TL;DR: The most simple tip is to keep your car clean and dry to eliminate chances of mold growth.


Is it safe to run an AC with mold?

No, it is not safe to run an AC with mold, and that includes the HVAC system in your home as well as your car.

Those with allergies or asthma are especially at risk when it comes to mold.

According to the CDC, exposure to mold can lead to minor symptoms like sneezing and stuffiness, but it can also cause severe reactions like breathing difficulty and fever.[4]

TL;DR: Mold is a health risk. Just don't turn your AC on if you suspect mold growth.

How much does it cost for a professional to remove mold from a car?

The average cost of paying a professional to remove mold from a car is $1200. Because of this high price tag, many drivers take the DIY route instead.

If the damage is severe, though, hiring a professional might be necessary.

ACLAB Note:

According to OSHA, it might also be necessary to consult a professional if mold is present in 10 square feet or more.

Large areas are difficult to deal with on your own, so call for backup if a large portion of your car is affected.[5]

TL;DR: It can get very expensive to hire professional service for mold removal from car. Hence it is recommended to prevent it from happening in the first place.


People Also Ask (FAQs)

How Long Does It Take For Mold to Grow in a Car’s AC?

It can take as little as 12 hours for mold to grow in a car’s AC.

Once the mold is present, it can start colonizing within the air conditioning system in 24 to 48 hours, so it’s important to act fast.

Is it Possible to Clean Mold Out of an Air Conditioner With Vinegar?

Yes, it’s possible to use white vinegar as an inexpensive mold-cleaning solution.

Vinegar has been proven to kill over 80% of mold species thanks to its mild acidity, and it’s a great option if you’re looking for a natural cleaner that won’t damage your car air conditioner.

References: 

  1. https://www.cdc.gov/mold/What-to-Wear.html
  2. https://www.epa.gov/mold/what-are-molds
  3. https://health.ri.gov/healthrisks/mold
  4. https://www.cdc.gov/mold/faqs.htm
  5. https://www.osha.gov/
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Josh Mitchell

Founder

Josh Mitchell
My name is Josh and I am obsessed with home appliances. From portable AC units to heaters and air purifiers, I enjoy testing, learning and using these devices to improve the air quality inside my family home.

My Favorite Home Appliance?

Midea U Shaped Window Air Conditioner

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