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Mold in Your Air Conditioner: How to Clean and Prevent Mold Growth in Your Central and Window AC Units

Mold is a naturally-occurring organism, and it certainly serves a purpose; however, it can also pose serious risks. The spores that mold produces can negatively impact your home’s air quality and can lead to health complications, particularly for those who suffer from allergies and who have been diagnosed with preexisting respiratory health conditions, such as asthma or COPD. Mold can grow in any part of your home, with common locations being the basement, attic, or bathrooms, but it can also grow in other locations that many homeowners don’t suspect, like an HVAC system. It’s bad enough when mold growth occurs in common locations, but it’s even worse when it happens in a ventilation system.

Why is mold growth in an air conditioner dangerous? How can you get rid of it? What can you do to prevent it from happening? For the answers to these questions and more, and to learn how you can protect your health and the health of your loved ones, keep on reading.

Why is Mold Growth in AC Systems and Units Dangerous?

Mold spreads by producing airborne spores. When those spores are floating about in your home, they can dramatically decrease the indoor air quality, and they can easily be inhaled. Exposure to mold spores can cause a range of adverse health effects. According to the US Centers for Disease Control and Prevention (CDC), exposure to mold growth can result in the following:

  • Nasal congestion
  • Throat inflammation/soreness
  • Coughing
  • Wheezing
  • Eye irritation (water, itchy, scratchy, redness)
  • Skin irritation

The type and severity of symptoms varies from person to person. Individuals with mold allergies are more likely to experience severe reactions when they’re exposed to mold. Individuals with compromised immune systems and who have chronic respiratory illnesses, such as asthma, chronic obstructive pulmonary disease (COPD), and emphysema are also more likely to experience complications, an in some cases, may even develop serious lung infections when they are exposed to mold spores.

Mold growth in an air conditioning system isn’t necessarily any more dangerous than mold growth in any other part of your home; however, due to the way an air conditioner functions, it is more likely to spread mold spores throughout various parts of your house, whereas the spores that are produced by mold growth in confined locations, such as in basements or bathrooms, are less likely to spread throughout your entire house. In other words, because HVAC systems and window air conditioning units are designed to spread cooled air, if there is a high concentration of mold spores in an AC, the chances of having a mold problem in other parts of your home, and thus, your air quality will be impacted more, and the likelihood that you and your family will inhale mold spores will be much higher. It is for these reasons that mold growth in air conditioning can be particularly dangerous.

How does Mold Growth in Air Conditioners?

Mold spores are literally all around us. They are constantly floating through the air and landing on sold surfaces. In nature, when those spores land on organic matter, such as fallen trees and leaves, they grow and feed on the matter, aiding in decomposition; hence, outdoor mold growth is actually quite beneficial. Of course, mold spores get inside, too. The microscopic spores float inside through windows, doors, chimneys, and ventilation systems. They can also attach to shoes, clothing, bags, and anything else that goes outside, and when those items are brought back inside, they become airborne, travel throughout your house, and land on all types of surface.

Try as you might, there is no way to completely eliminate mold spores in your house. Minimal concentrations of mold spores usually aren’t problematic; the problem arises when those spores continue to multiple and become mold. Why? Because patches of mold release spores, and the concentrations of the spores that mold growth produces can be quite high. That’s where the problem lies, and where adverse health effects as a result of mold exposure can occur. Since it is impossible to stop mold spores from entering your house, in order to prevent the negative effects that mold exposure can cause, you need to work on preventing the spores from growing into the fungi.

In order to grow, mold needs just a few basic things:

  • Moisture
  • Warmth (temperatures above freezing)
  • Food (organic materials)
  • Dimly lit conditions

Moisture in your home can occur for a variety of reasons; high humidity levels, poor ventilation, a pipe leak, a flood, or even something as simple as a drink spilling or a pet accident that wasn’t fully dried, for example. Food sources can include anything organic, such as wood, linens, rugs and carpeting, rug and carpet padding, grout, insulation, or even the organic particles found in dust, such as dead skin cells and pet dander. There’s no doubt the temperature in all areas of your home is above freezing, and dimly lit conditions can occur in virtually every room, such as under carpets, in nooks and crannies, in basements, underneath appliances, and in cabinets. As long as the elements that mold needs to grow are present, the airborne spores can accumulate, grow, and spread. In other words, mold growth can occur in virtually any part of your home.

Typically, HVAC air ducts and air conditioners aren’t hospitable locations for mold growth. They sheet metal that HVAC air ducts are made of and the Styrofoam channels that are found inside window units aren’t organic, and thus, they don’t provide mold with a source of food. With that said, however, dust can collect in these areas, and because dust is usually comprised of organic matter, combined with the fact that air conditioners generate moisture, they can most certainly serve as a hotspot of mold growth.

Is There a Way to Get Rid of Mold in an Air Conditioner?

Getting rid of mold can be a complicated, messy, and frustrating task. The location where the mold is growing needs to be properly ventilated when you’re cleaning, otherwise the spores can be released and recirculated, exacerbating the problem. Additionally, wearing protective elements, such as a face mask, non-porous gloves, and googles is highly recommended; particularly if you have a sensitivity to mold. With that said, however, as long as you protect yourself and make sure that the space is well-ventilated, you can effectively clean up mold. Here are some tips that you can use to clean mold from both single air conditioning units, such as window or stand-alone units, and central air conditioning systems.

  • Stand-alone air conditioning units. By the time you notice spots of mold growing in a stand-alone unit, such as in the air direction vanes or on the grates of the unit, it’s almost certain that the mold you’re seeing is a sign of a much bigger problem. The visible mold is just the tip of the iceberg, and it’s likely growing throughout the unit, such as in the evaporators, ducts, and coils. You can try to disassemble the unit to remove the mold; however, it’s likely that you won’t be able to completely eliminate it or that it will just grow back. As such, when mold is growing in a stand-alone air conditioner, replacing the unit is your best bet.
  • Central air conditioning. Mold can grow within the ductwork of a central air conditioning system, and when it does, hiring a professional to remediate the issue is highly recommended. As per the US Environmental Protection Agency (EPA), if you suspect or detect mold growth in a central AC, you should turn off the system right away, so as to stop it from further spreading throughout your home. The ductwork will have to be thoroughly cleaned and vacuumed, so as to ensure that all traces of mold spores are removed, and doing so can be complicated and frustrating; not to mention the fact that there’s a chance that you could damage the system or injure yourself. Thus, having an HVAC professional do the job for you is recommended.

Can You Prevent Mold Growth in Air Conditioners?

In order to prevent mold growth in any area, proper moisture control is essential. Air conditioners produce moisture, so it isn’t uncommon for mold growth to occur in both HVAC and stand-alone units. So, how can you prevent mold growth from occurring in your AC? Here are some tips that you can use to control moisture content, and thus, reduce the risk of mold growth.

  • Make sure that window unit ACs fit properly in the window. Doing so will prevent moisture from rain and outdoor humidity from getting into the space.
  • Make sure that window units are slightly tilted toward the exterior of your home. Doing so will allow condensation buildup to drain out of the unit, which will reduce the risk of mold growth.
  • Clean the grates and filters in your stand-alone units on a regular basis. Doing so will help to prevent dust from accumulating, minimizing the buildup of organic matter, and thus prevent mold growth from occurring. Plus, cleaning the grates and filters on a regular basis will also help to ensure that the flow of air won’t be impeded.
  • Whole house air conditioning units should be equipped with proper drainage, which should lead to a drain tile, through the slab of a basement, or to a utility sink, for example. Check to make sure that the drainage is working correctly so that moisture doesn’t accumulate around the unit or make its way into the ducts. Drains can get clogged up with dirt and debris buildup, which can lead to flooding that can cause mold growth.
  • Periodically empty portable air conditioning units. Usually, these units are equipped with auto shut-off features, as well as an indicator light that will alert you to as to when the reservoir is full.
  • Be sure to replace air filters on any type of air conditioning unit on a regular basis. If the filters become clogged with dirt and debris, not only will mold be able to grow as the dirt and debris will provide a food source, but the flow of air will be impeded.
  • Never, under any circumstances, purposely introduce moisture into an air conditioning system. Dry vacuuming, not wet vacuuming, should be used when cleaning out air ducts. If you are wiping any component down, use dry cloths; do not use water or cleansers.

Summing It Up

Mold growth in an air conditioner unit or an HVAC system is a serious issue, as the mold spores can spread throughout every room in your home, increasing exposure and the risk of health complications. If you are positive that mold is growing in your home’s HVAC system, contact a reputable professional to address the problem. If you’re certain that mold is growing in your window or stand-alone units, investing in new appliances is highly recommended, as it’s virtually impossible to remove the mold growth. Even if you don’t suspect that mold is growing in your home’s air conditioning units or HVAC system, hiring a mold inspection and testing company is highly recommended. Just because you can’t see it doesn’t mean that mold isn’t a problem. An experienced professional from a reputable company, like Mold Testing and Inspection (MI&T) will perform comprehensive testing of your home’s air and surfaces. If it is determined that mold growth is present in your home, recommendations to address the problem will be made so that you and your family can breathe freely.