8 Clear Signs You Have Mold Infestation in Your HVAC & Vents

by | Nov 15, 2023 | Mold | 0 comments

While mold sometimes grows in visible areas, it tends to thrive in dark, damp, and tucked away areas like in basements or crawl spaces, behind appliances, or in pipes and air vents. In fact, HVAC and ventilation systems are among the most common places to find hidden mold.

Without intervention, mold in AC vents can damage your heating and cooling system, decrease your property value, and cause allergies and other health issues. But household mold is a very common issue – and a fixable one!

The first step to getting rid of household mold is to identify the source of the problem. We’re bringing you 8 signs you may have mold in your HVAC system and what to do when you find it!

The Impact of Mold in HVAC Systems

Mold spreads by producing microscopic spores that travel through the air and land on various surfaces in your home. Because HVAC systems facilitate airflow and regulate temperature throughout a building, a mold infestation in these systems can lead to rapid proliferation.

Residential mold presents a number of concerns for your physical well-being and your home. Mold in your HVAC system can pose a risk to your health, negatively affect indoor air quality, and reduce energy efficiency.

Common Signs You May Have Mold in Your HVAC & Vents

woman lying in bed sneezing

Sign #1: A Musty Odor

If you notice an earthy or musty smell that won’t go away or gets worse near air ducts and vents, you may want to have your HVAC system tested for mold. Mold commonly emits a strong odor by releasing microbial volatile organic compounds (mVOCs) into the air. This persistent, earthy smell is often one of the first signs of a mold infestation.

Sign #2: Allergic Reactions

Mold is an organic irritant and allergen that can result in several unpleasant health effects to those exposed. Common symptoms of mold allergy include:

  • Itchy eyes, nose, and/or throat
  • Sneezing
  • Coughing
  • Excess mucus in the throat
  • Dry or rough skin
  • Runny or stuffy nose
  • Shortness of breath
  • Tightness in the chest

If any of these symptoms persist or worsen overtime, HVAC mold may be the culprit.

Sign #3: Visible Mold Growth

Depending on the design of your ventilation system, you may be able to see visible mold growth in and around vents. Mold in AC vents and other areas of your home can appear in various different colors depending on the species, humidity level, amount of light exposure, and other factors. But in most cases, mold is identifiable by its raised, fuzzy texture and splotchy appearance.

Sign #4: Increased Energy Bills

Have you been getting higher-than-normal energy bills and you’re not sure why? Mold in AC units and ventilation systems can increase your utility bills by negatively impacting your air conditioner’s efficiency. When mold accumulates in your system, your units have to work harder than usual to effectively cool the same space.

Sign #5: Respiratory Problems

When it comes to physical symptoms of mold exposure, respiratory issues are one of the most common. Indoor mold can result in breathing problems for anyone, but it’s especially harmful to the elderly and those with underlying respiratory conditions such as:

If breathing problems suddenly occur or worsen, it’s a good idea to check your home for mold.

Sign #6: Water Leaks or Condensation

Moisture accumulation is a common cause of indoor mold and mildew. That’s why it’s often found in places like bathrooms and plumbing systems, on window sills, or after flooding has occurred. Leaks and condensation in and around your HVAC systems create an ideal environment for mold spores to land and reproduce.

You can help protect your system by routinely checking your unit’s drain and condensate pans and inspecting ducts and other components for signs of moisture.

Sign #7: Poor HVAC Performance

In addition to reducing energy efficiency, mold in your HVAC system can actually damage its ability to regulate temperature and provide adequate airflow. If you keep turning up your AC and it just doesn’t seem to be working properly, you might want to check for mold.

Sign #8: Excessive Humidity

Mold is naturally attracted to damp or moist environments, so it’s no surprise that excess moisture in your home can lead to mold growth, especially in your HVAC systems. Setting up a dehumidifier to control moisture and using a hydrometer to monitor humidity levels (below 50% is ideal) can help prevent mold.

How to Address Mold Infestations in Your HVAC & Vents

fan unit on side of building

Your heating and cooling system helps to circulate and filter the air you and your family breathe every day. If there’s a mold problem, you need to know about it. If you’re experiencing any of the signs discussed above, it’s important to check your system for mold.

If you or your inspector/technician notice any build-up or other signs of mold, consider getting a professional mold analysis at an accredited lab like JSE Labs. The process is straightforward and quick – you can even get same-day results in most cases! Simply mail a sample to our lab and we’ll get back to you with accurate results.

If your analysis comes back positive for the presence of mold, don’t worry. There are steps you can take to remove mold from your home and prevent it from returning in the future.

Preventing Future Mold Growth

When it comes to HVAC mold, prevention is generally easier and less expensive than removal. Keeping humidity levels low and staying up-to-date on routine HVAC maintenance will help keep your system in good condition and allow you to catch any early signs of mold before it gets worse.

There are times when mold growth is more likely to occur and more aggressive prevention strategies may be necessary, such as after water damage and during the winter months.

Get Reliable Mold Testing & Protect Your Home & Family

female scientist looking in microscope testing for mold

If you’re dealing with allergy symptoms, an odd musty smell near your vents, or an increase in your monthly energy bill, you may have a mold infestation in your HVAC system. JSE Labs provides safe, accurate, and convenient mold testing and analysis to homeowners and commercial property owners at our accredited environmental laboratory in Milwaukie, Oregon.

Contact us today to learn more about our services and find out how we can help!

Jennifer Malgren

Jennifer Malgren

Jennifer is the Laboratory Manager of JSE Labs, and holds a BS in Environmental Studies & Science from Portland State University. She is an avid learner and enjoys exploring new topics related to natural processes and the environment. She has experience analyzing hazardous materials, including asbestos and lead, and is committed to promoting safe and sustainable practices in the workplace and beyond. When not in the laboratory, Jennifer can be found exploring the Pacific Northwest with her Catahoula Leopard Dog, Oliver, or volunteering locally.

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