Is Mold In Your HVAC Dangerous?

One of the worst places for mold to develop is in your HVAC. Not only can it present health hazards, but it can seriously harm the machinery.

Even though it’s not always harmful, mold should be eradicated as soon as it’s spotted. Here we dive into what can be done to prevent mold growing and returning in your HVAC system.

How Mold Affects HVACs

Mold thrives in warm, humid, and dark environments. Your HVAC interior can be just that, especially if underused.


The air conditioner eliminates moisture from indoor air as part of its routine operation. While doing this improves the comfort level in your home, it can also result in moisture condensation as air moves through the air conditioner. If you notice any leaks around your air conditioner, fix them immediately to prevent the spread of mold. It may get worse if your home has high humidity levels. To prevent mold growth, it is advised to keep these levels below 50%.


For most of us, a comfortable temp range is between 60 and 80 degrees Fahrenheit, which is also the best range for many fungi, including mold. These temperatures, when combined with high humidity levels, can promote the growth of mold. Furthermore, the issue is exacerbated by temperature variations inside your house (for example, warm air coming in contact with a cool surface causes condensation).


Mold requires organic matter to grow, which can be found in your home’s dust, skin cells, pollen, or other indoor air pollutants. The majority of these contaminants can pass past air filters and build up in the ducts or other parts of the system, which helps mold grow.

Mold and mildew issues in air conditioners can be made worse by other typical air conditioner issues. For instance, clogged condensate drains result in water backup inside the appliance, which promotes the growth of mold. Additionally, anytime the HVAC system is not in operation for an extended length of time, water droplets tend to accumulate in the air handler or ducts. Mold can thrive in these conditions of increased moisture and organic materials in the air, such as dust or skin particles.

Mold in Air Conditioners: Telltale Signs

Although mold within air conditioners isn’t usually immediately apparent, certain signals can tip you off. These typically result in health issues – such as allergy like symptoms or respiratory problems. It could be time to contact a mold expert if someone living in the home has recently seen changes in their health without a clear cause.

mold sicknessHere are a few typical health effects of mold in your HVAC:

  • Coughing
  • Sore throat
  • Nasal Congestion
  • Rashes or itching skin
  • Wheezing
  • Itchy and watery eyes

A perceptible musty odor around the air vents in your home that gets stronger when the system is working is one more red flag to look out for. Additionally, look for mold growth near drip pans, evaporator coils, and vents.

Is your HVAC system making you sick?

It’s alarming and dangerous for your health and home if mold is developing anywhere in the house. Anyone with allergies or a weakened immune system, such as young children or the elderly, may experience particular stress.

Your airways and lungs may become inflamed as a result of exposure to mold. Additionally, it can exacerbate asthma symptoms, skin irritation, mold allergies, shortness of breath, and underlying respiratory issues.

Additionally, some people may have headaches, hives, runny noses, itchy eyes, and rashes. Fatigue, nausea, and dizziness are among less frequent signs of mold exposure, and some reactions can be fatal.

How Can Mold in Air Conditioning Systems Be Removed?

Depending on the model of air conditioner you have, getting rid of mold in it may be fairly straightforward. However, while cleaning the mold from the window AC unit is simple, doing the same for the entire central air conditioning system would require more work. When addressing a mold infestation, you have a number of options.

Change the unit

If there is extensive mold growth, replacing the appliance would be significantly less expensive than having the mold removed. For smaller and less priced free-standing or window units, this is especially true. However, it could be easy to accidentally overlook some spots while removing mold from an HVAC unit that’s badly affected, which could then encourage regrowth following removal.

Hire an Expert

If throwing away a working AC unit doesn’t appeal to you, and if the mold isn’t widespread, the best course of action is to hire an expert. Mold in the air conditioner can be entirely removed with the aid of a professional cleaning procedure. If you have central air conditioning, this is most likely your only option.

Do It Yourself

You might be able to self-clean the mold in your air conditioner if you’re fortunate enough to have a compact, detachable unit with minimal damage. Since there is always a possibility that you can spread the mold to other areas of your house, the majority of specialists don’t advise using this strategy. But if you decide to go down this road, there are several precautions you can take to make sure the process is handled carefully.

To protect yourself from mold exposure, grab some gloves, goggles, and face masks. To prevent mold spores from landing on your clothing or any exposed skin, you can also put on a protective suit.

  • To prevent cross-contamination across your entire home, relocate the unit to a separate area.
  • Open the container, examine it, and assess the project’s overall simplicity. Is the mold, for instance, greater than a third of the unit? Is it tough to get to the moldy places? If so, you should either replace the unit or leave the project to a professional.
  • If your response to the questions above was “no” and you still wish to carry out this procedure, remove the filter and throw it away if it is disposable.
  • Remove any visible mold and dirt from non-disposable filters before immersing them in a solution of 10 parts water to 1 part bleach. After 10 minutes of soaking, rinse it out and let it air dry.
  • Clear the interior of the device of any debris.
  • Deep-clean any unit surfaces that have been impacted using the cleaning solution from step 5. For added power, add a teaspoon of detergent.
  • To eliminate any lingering mold spores, allow the mixture to settle on the surface for ten minutes.
  • Avoid touching any electrical parts while carefully rinsing the appliance, and then let it air dry.
  • Reinstall the filter after reassembling the unit.

How Can You Avoid Mold in Your HVAC?

While there is no foolproof method to prevent mold growth in your HVAC, there are several precautions you may take to lessen the likelihood that the problem will arise.

  1. Regularly — every 30 or 90 days, or as advised – replace your HVAC filters.
  2. Use a mold-control-specific type of air filter, as they have higher MERV ratings than the alternatives. Better filters can help get rid of organic matter in the air that feeds mold colonies.
  3. Use a UV light air purifying system to eliminate mold spores in the air and enhance overall air quality with your existing HVAC system. To lessen condensation inside air ducts, seal and insulate them.
  4. Empty drip pans on a regular basis and rinse them with bleach to get rid of festering colonies.
  5. If your home has too much humidity, especially if you live in a place with a lot of moisture, use a dehumidifier.
  6. Get a professional to evaluate your HVAC system every year to look for mold in the air conditioner or other parts.
  7. When on vacation, don’t turn off your air conditioning (especially in hot, humid weather), as mold tends to accumulate in systems that aren’t in use. Since only air movement is needed, you can increase the temperature of your air conditioner. In this situation, using a smart AC controller to remotely operate your device is the best course of action.
  8. Moisture, heat, and nutrition are necessary for the growth of mold spores. It’s imperative to act if you notice visible mold growth or a musty stench. Ignoring the issue could endanger your health severely in the future.

Filter replacement on a regular basis, annual HVAC maintenance, and maintaining proper humidity levels are all crucial steps in lowering the likelihood of mold formation in your house.

If you suspect you have a mold problem, or just need help with regular HVAC maintenance, get in touch!

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