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How to Know If There’s Mold in Your Air Ducts

March 10, 2023

mold in air ducts

Around 70% of homes in the U.S. contain mold. Although the problem might be more common than you’d think, mold in air ducts can cause all manner of problems.

This is especially dangerous if you have elderly people, small children, or those suffering from respiratory problems in your home. But many people don’t know how to identify this issue, or how to deal with it once it occurs. Mold may be thriving inside your air ducts without your knowledge.

Want to learn more about how to spot the signs of mold in an air duct and how to deal with the issue when it arises? We’ve got you covered. Keep reading to find out everything you need to know.

Visible Mold

You should always start with the eye test. By taking a look at your air ducts, you may notice there are signs of mold on the outside. This could come in the form of small specks around the exterior grille.

Going one step forward, you can remove the grille and look inside the vent. You may notice mold thriving there. Most people don’t tend to check this area very often, but it can multiply in the dampness and darkness inside of a duct.

Please note, just because you can’t see mold doesn’t mean that it isn’t there. Carrying out the eye test is a great way to start your hunt for mold, but it’s not a magic bullet. Sometimes mold can be growing deeper in the ducts, with spores spreading throughout your home when your HVAC system activates.

A Strong Odor

The clearest sign of mold in the air ducts is an odor. This should smell damp and musty. You might notice the smell anywhere in your home, but it should be particularly prominent when you’re standing close to air ducts.

A similar odor can be caused by some other things. For example, mold in other areas of your home, or even clothes which took a little too long to dry can smell musty.

Signs of Mold in the Home

You might notice mold has spread from the air ducts and is appearing around your home. It may be spotted in any room of your home, but especially in typical areas for dampness, such as the corner of a roof.

Physical Symptoms

Mold can cause physical symptoms in a high number of people. If you’re experiencing unexplained physical illness symptoms, mold could be the cause.

You may suffer these symptoms more often when the AC is running. This is because air is moving through the air ducts and spreading around your home. You may inhale the spores, causing your body to react badly.

If you’re suffering from these symptoms, be sure to consult your physician for immediate guidance. Mold is just one of several possible causes of these issues, but other issues may be at play here too.


A mild to moderate headache can be caused by mold. If you’re noticing a headache every time the AC is turned on, alarm bells should be ringing.


Nausea is another common physical symptom. You might find yourself feeling a little sickly when the air con comes on, and this should raise red flags for you. Mold spores can cause your body to try and fight back against invading substances, and this can cause a nausea response.


We all feel tired sometimes, but if you’re constantly fatigued, it may be due to mold. If you’re exhausted even after getting a good night’s sleep, mold may be the reason why.

Other Symptoms

There are several other symptoms caused by mold. These include difficulty breathing, watery eyes, and diarrhea.

People with asthma or other respiratory issues may be especially vulnerable to the negative impact of mold. If you suffer from these issues, it’s doubly important that you check with a physician immediately if you’re experiencing these symptoms.

Basic Prevention Steps for Mold in Air Ducts

If you’re looking to keep mold out of your home, there are a few simple steps you can take. This should help you control the problem while you wait for help.

First of all, you should ensure all the rooms of your house are well aired out. If you suspect your air ducts may be packed full of mold, you may want to avoid opening the ducts. So, the best way to keep your property well-aired is to simply open the windows for at least a little time every day.

But to deal with a major mold infestation in your house, you’ll need the help of experts. Only trained professionals can get deep into your HVAC system and ensure it is totally clear of mold.

Next, you ought to clean up any mold when you find it. Mold removal is normally quick and easy and it can help to improve the air quality in your home. Use a cloth and an anti-mold spray to clean it off and cover your face to stop yourself from ingesting any dangerous spores.

Improve Your Air Quality With a Quality St. Louis Company

When you have mold in air ducts, you’ll be eager to clean things up as soon as possible. You need a reliable local company to help as soon as possible.

Anton’s Air Conditioning and Heating Services can help. We offer a range of services to help you enjoy clean air in your home, from duct cleaning to HVAC maintenance. Contact us today to find out more about what we can do for you.

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