What Kind Of Mold Grows In Window Air Conditioners? What You Need To Know

Helen Skeates
Helen Skeates
14 min read

Mold is a no-no! Mold is a horrifying sight, regardless of whether you’re a tenant or a homeowner. In addition to that, it might be harmful to one’s health.

Mold can grow in your air conditioner, which is something you would not expect. Mold can grow in the air that circulates through a space.

When the AC is on, you can smell the distinct odor of black mold. When the air conditioner has been running for a while, you can even smell it. Because mold allergies can cause sneezing and coughing, you’ll be able to determine when your allergies are activated. Those who suffer from severe allergies or asthma should avoid it at all costs.

Mold in Air Conditioners: How to Clean and Prevent Growth | Molekule Blog

Occasionally, mold can be seen growing on the air conditioner’s filter or on the inside of the appliance itself. Regardless matter how you discovered the mold, it’s time to get rid of it!

A little background information on the type of mold that forms in window air conditioners is necessary.

What Kind of Mold Grows in Window Air Conditioners?


This form of mold is known as “black mold” because of its greenish-black hue. Paper, lint, dust, fiberboard, and gypsum board are the most common substrates for its growth.


When it comes to mold, summer is the best time to find it because it thrives in moist circumstances. Humidifiers and pools of still water contain it.


Acremonium, like Fusarium, thrives in moist conditions. Hay and other dead plants are common locations for it. Building materials that have been exposed to water, or air conditioners might also contain it. Humidifier water is one possible source of Acremonium in the home.


This type of mold is quite invasive. It thrives in damp situations, such as air vents, where it can thrive for lengthy durations. It has the appearance of spores and spreads swiftly, making it a serious hazard to your property.


Water-damaged building materials are the most typical source of this particular mold. You can also come across Alternaria in flooded areas and humidifiers.

Why do window air conditioners get mold?

They have standing water inside the housing.

Contaminated water is a sure sign of a puddle. Mold thrives in damp, gloomy environments that have a constant supply of stagnant, tainted water.

The term “condensation” refers to a small drop from the back of the air conditioner.

How can a window AC unit’s mold be avoided?

If there is a significant amount of water in the area, It can only suggest that anything is preventing the air conditioner’s condensate from draining out the back.

This means you’ll need to remove the air conditioner from its housing to clean away any dirt that is preventing the air conditioner condensation from draining.

This includes cleaning out the air conditioner’s interior and exterior of any debris preventing the condensation water from draining or dripping out of the back of the air conditioner.

Another thing to keep in mind is that this type of material can only enter the back of the air conditioner through the filter slots on the machine’s top and sides if it is immediately below a tree or other large, rotting object.

It’s important to clean the area around the air conditioner and make sure it’s not in a place where anything could get in, and to close the drip hole.

Since the air conditioner has already been disassembled and the problem has been identified as a blocked drip hole,

It’s simple to do and won’t affect the air conditioner’s efficiency in any way, but it will help prevent moisture from accumulating in the machine’s bottom.

Make a hole at least 3/8 inch deep in the bottom of the air conditioning unit with a drill bit. Adding this will allow condensation to enter the air conditioner from below.

Putting the filters back in when they’re wet.

For air conditioners that aren’t cooling well, the first thing you should check is the air filter.

It is impossible for air to enter your home if it cannot pass through the filter.

Nonetheless, it is crucial to remember to properly dry the filter after washing it with water.

Mold spore formation can be restarted by putting the moist filter back in. Water and a deep, enveloping gloom.

Improper storage

If you’re going to store your air conditioner, make sure it’s in a dry spot with no access to water, or wrap it tightly in plastic wrap to keep the insides dry.

Air Conditioner Mold | Smelly Air Conditioner | Mold In Air Conditioner

Mold is kept at bay by the design of window air conditioners. In reality, one of the primary causes of dry air is central air conditioning.

Dehumidifiers, which are designed to lower indoor humidity, work in much the same manner as window air conditioners.

As a result, if you’re having an issue with mold growth in your window AC,

Similarly, swamp coolers and evaporative coolers have the same mold issues.

The only drawback is that they need water to circulate inside the machine in order to produce cool air.

Mold can grow in swamp coolers for a number of reasons, including:

Allowing the water to stand inside the housing when the unit is not in use.

After turning off the water supply, the swamp cooler still receives water from the source, even though it has been switched off.

The best way to prevent mold growth in your swamp cooler is to keep it spotless at all times.

Don’t allow water to accumulate within the unit when you’re not using it. Also, make sure that the pads are completely dry. It’s important to ensure that the water is completely shut off and that there is no water dripping into the pads.

Keeping an evaporative cooler clean and mold-free is an essential element of utilizing an evaporative cooler.

In addition to removing the pads, the machine must be properly emptied and let to dry before being used again.

Use a rain and snow-proof cover to completely encircle the device so that it is totally dry.

Keep an eye out for vermin who prefer to make their bed in a swamp cooler that hasn’t been properly packed away. Mice and rats can use the drain plug as a front door because it’s just the perfect size.

How mold grows in air conditioners

It’s impossible to avoid mold spores. Even if you were able to eliminate all of the mold spores in your home, more would continue to enter your home every time a door or window was opened. It is the increasing levels of spores released as a result of mold growth that create the health issues linked with mold exposure. As a result, preventing mold growth is the most important step.

Mold thrives on two things: wetness and an organic food source. When there is a leak or spill that is not adequately cleaned up, moisture can build up. If the condenser and evaporator coils are not properly drained, water can seep into the system and cause damage. If there is enough organic material in the air, the mold can feed on the surface it is growing on, such as wood or carpet.

Mold can’t thrive in air conditioners and HVAC ducts under normal situations. Mold cannot grow in window unit ductwork or styrofoam pipes since they are not food sources for the microorganisms. However, dust can accumulate in these areas, allowing mold to thrive.

How do I get rid of mold in my air conditioner?

Mold removal from an air conditioner can be tough, messy, and dependant on the type of device. Window AC units, car AC units, and central AC units all require different amounts of cleaning supplies to be mold-free. In order to protect yourself from mold spores, you should always work in a well-ventilated location while wearing non-porous gloves and a face mask with goggles. A home cleanser and a sponge or cloth can be used to remove mold. Mold can be removed without the use of bleach. Getting rid of mold that has grown on porous materials like wood or plaster will likely be difficult, as would removing mold from carpet or upholstery. Remove, dispose of, and replace the moldy object or piece.

It’s generally too late to fix a window unit’s air direction vanes or grate when you notice little mold spots appearing on the surface of the unit. Just a little portion of what’s lurking beneath the surface. Even if you dismantle your air conditioning unit and thoroughly clean all of its components, there’s always a chance that you’ll miss a spot and allow mold to grow back in its stead. In most cases, it’s best to get a new window unit to replace a moldy one.

Your central air conditioner’s ducting is likely to be infested with mold if it’s not properly cleaned. In order to prevent mold from spreading, it is recommended to turn off the air conditioning system as soon as possible. Vacuuming and cleaning the ducts will be necessary, and if the contamination has spread throughout the system, this might be time consuming and costly. It is significantly easier to clean sheet metal ducts compared to ducts made of fiberglass or plastic. Using biocides or surface treatments to kill or prevent mold in ductwork is not recommended by the EPA.

Cabin Air Filter: Under typical operating conditions, the cabin air filter in your automobile should remove at least some spores of mold from the air. The cabin air filter should be replaced as soon as possible if your automobile gets wet from a flood or if you leave your windows open in the rain. There are only a few things you can do if mold grows in your air conditioning system. With household cleansers and a soft cloth, you can remove the dashboard and clean most of the ductwork. If the ducts are really moldy, they can be changed, although the cost and work needed varies from vehicle to vehicle. While some chemical products are available for use in the air conditioner, their usefulness is questionable and any chemicals you put in it will be dispersed back out into the air for your inhalation.

What Should You Do If You Suspect Mold In Window Air Conditioner Units?

Do not turn on your air conditioner to begin with! If it’s on, shut it down and don’t switch it back on until you’re sure it’s mold-free or have it replaced. When utilizing an air conditioner that may contain mold, the U.S. Environmental Protection Agency (EPA) recommends that you avoid doing so because the air will carry microscopic mold spores with it. Mold spores that are too small to see can readily be inhaled and cause illness. To keep mold from spreading, the air conditioner needs to be running constantly. When the air conditioner is turned off, mold spores can fall to the floor and land on carpets and furniture, where they can begin to develop if the correct conditions are present.

It is possible to evaluate your window air conditioner for symptoms of mold by looking at it. Find any visible mold by using a good light source. Inspect the filter, too, after removing it from the device. Even if you don’t see mold, you should be aware that it could be present. Mold can be difficult to detect in small numbers, and depending on where the mold is growing in the air conditioner unit, it may be impossible to notice it without dismantling the machine.

You could hire a professional mold tester to check the unit for mold, but buying a new air conditioner would be less expensive in the long run. These days, the majority of window air conditioners are very reasonably priced. The likelihood is that you are correct if you suspect mold in your air conditioner. If you suspect mold in your air conditioner, you may want to hire an expert to do a mold test before making a purchase. Instead of paying for a mold test, you could just go out and get a new device. As a result, you’ll likely save money in the long run.

What Should You Do If You Determine There Is Mold In Window Air Conditioner Units?

The first step is to remove the moldy unit. Do not activate it. Remove it with a simple swipe of a finger. In order to avoid dispersing mold spores around your home during removal, wrap it tightly in heavy plastic before moving it.

This isn’t enough, unfortunately, to guarantee mold-free living conditions in your house. In light of the high probability that mold has already spread, we advise that you investigate all areas of the room for symptoms of mold. It’s a good idea to examine around the air conditioning unit and the window where it was installed, as well as the wall and possibly even within it (you can learn more about mold in walls here). Mold can be difficult to notice in dark places, so use a powerful flashlight to check for it.

When it comes to making sure the room is clear of mold, a mold remediation professional can come to your home, inspect for the presence of the mold, and advise you on the best course of action. There’s no charge and no commitment to use this service at all. For qualified professionals in your region who give free consultations, simply click on the link provided.

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Mold in Air Conditioner Heath Risks

Black mold on an air conditioner isn’t a problem for most individuals.

People and pets who suffer from asthma, COPD, allergies, or any other type of breathing disorder may be particularly vulnerable to the health effects of mold in the air conditioner. Inhalation of mold spores poses a health risk to elderly adults and their pets, even if they are otherwise healthy.

Stachybotrys chartarum is the scientific name for black mold. CDC: Stachybotrys chartarum and other molds may produce non-specific health issues. This is according to the CDC. Finding out what kind of mold is growing in your home or other building isn’t necessary. The removal of all molds should be done.


For window air conditioners, you need to know what kind of mold grows in them before you start cleaning them. It’s important to pay attention to the scientific names of these substances because they reveal important information.

It doesn’t matter how much money you spend on your window air conditioners if you don’t take care of them. It’s important to remember that you bought this to improve the quality of the air, and it won’t do that if it’s moldy.

Helen Skeates

Helen Skeates

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