How Can I Tell If There Is Mold In My Air Ducts?

By Dan WienerLast update
How Can I Tell If There Is Mold In My Air Ducts

No matter the climate you live in, your air ducts can be an excellent host to a wealth of mold strains, with some causing moderate to adverse health problems. Avoiding frequent maintenance of your air ducts can be detrimental to your health and that of your family. Furthermore, air duct mold is more hazardous to seniors, pets, infants, small children, and anyone whose immune system is compromised.

If you’re wondering, ‘how can I tell if there is mold in my air ducts?’ you’ve come to the right place. When there is mold, you can usually smell a musty smell around the air vents. You may also experience allergy-like symptoms and sickness.

Read on to find out more about how to tell if there is mold in your air ducts.

What Triggers Mold Growth In Ductwork?

Mold thrives in air ducts when warm temperatures and moisture are present. A warm, humid environment has the most suitable conditions for mold to flourish. With poor ventilation, moisture gets trapped in the walls, causing condensation. As a result, mold forms on the ductwork. Here are some of the HVAC issues that may contribute to mold growth.

An Oversized AC Unit

If you have a unit that’s too big for your home, mold is likely to grow in the ductwork. Bigger units can cool small spaces quickly and turn off before dehumidifying the air, causing excess moisture. The buildup of this moisture results in the growth of mold shortly after a new installation. Make sure to listen to professional advice on the HVAC unit that would be perfect for the size of your home before the installation.

Setting Your AC On Low Temperature

When your HVAC is set at an overly low temperature, it can cause mold growth around the ductwork. That’s because cool air from the air ducts meets the warm air in the room. Temperature differences may cause the moisture in the air to condense on the surfaces and around the ductwork.

If this moisture doesn’t get a chance to dry, it builds up and forms the perfect breeding ground for mold. The process is known as temperature differential and typically takes about a 20-degree difference to form moisture. If the moisture goes unnoticed for weeks or months, it inevitably makes its way into your air ducts.

Leaking Ducts

If your ductwork is leaking, that means warm air in the atmosphere seeps through, causing a temperature differential. The difference in the warm air in the walls can result in the condensation of moisture on the ducts, ushering in the perfect environment for mold growth.

If that’s the case, you’ll require a thorough duct cleaning with mold remediation. Furthermore, you’ll want to ensure you properly seal the ducts to curb the problem from recurring.

A Musty Smell When Your HVAC Is On

When there’s a large presence of mold, you’ll notice the unit emitting a pungent odor that can be described as earthy or musty. Although the smell might be unpleasant, the good news is that larger mold infestations are easier to detect.  

When you have mold buildup in your ductwork, the smell is typically the strongest when the unit is running. That’s because the air that stems from your ducts will collect and carry more spores as the mold spreads. Spores will settle into the ducts when your system isn’t operating, making the odor harder to detect.

Allergy Symptoms and Illness

There’s no greater health risk for you and your family than the buildup of mold in your ductwork. While inhaling mold spores can trigger symptoms in anyone, some people are more susceptible to allergic reactions. Similarly, mold can exacerbate the symptoms of anyone in your household with respiratory illnesses.

Allergy symptoms ranging from difficulty breathing, itchy, sneezing, and watery eyes to coughing can be triggered by mold if they occur indoors, particularly if they’re more adverse in air-conditioned spaces. In more chronic instances, breathing mold spores can result in confusion, fatigue, diarrhea, nausea, and vomiting. If you notice these symptoms, stop using your HVAC unit and call a professional for a thorough inspection.

Visible Mold On Air Ducts

The air from your air HVAC unit initially comes into contact with your vents before it makes its way through the rooms in your home. Therefore, it’s not unusual to see considerable mold buildup on the vents.

Spores will settle on your vents in the form of small spots that are typically white, black, or green. Even though you don’t notice mold outside your vents, you should occasionally remove and examine them for mold growth on the side facing the duct.

Cleaning the mold off your vents will naturally make them look better while preventing allergy symptoms and illness as it’s no longer growing directly in the room. To get rid of mold from a vent register and improve indoor air quality:

  1. Remove the vent cover and immerse it in water
  2. Add laundry detergent
  3. Let the vent cover soak
  4. Vacuum the exposed duct work to get rid of as much mold as you can out of the duct system

Mold In the Air Conditioner or Furnace

The same environment that promotes mold growth in your ductwork is also prevalent in your air conditioner and furnace. Mold can grow on nearly all dark and damp surfaces. The mold in your ducts might have stemmed from appliances that spread it through the ductwork when your HVAC was running.

The most common places to notice mold in an AC are in the drain pan below them or evaporator coils. These components are frequently coated with condensation that may provide adequate moisture for mold to thrive. You might notice mold anywhere on your furnace as it heats and humidifies the air in it.

Other Areas In The Home Where Mold Typically Accumulates

Source: Virunja

Mold can thrive below the fridge, next to the motor area, on the bathroom walls and ceiling, below the bathroom sinks, and underneath the kitchen. That’s particularly true when the bathroom lacks a window, and the only ventilation source is a vent fan.

Therefore, it’s essential to ensure that the bathroom vent fans function optimally and ward off the unwanted moisture from a steaming shower. The ideal operation of the fan should be a clear exhaust and vent line outside the home. Typically, contractors will connect the exhaust to the vent and right into the attic, causing moisture buildup that may result in a mold problem.

Prevention Is Better Than A Cure

Now that you know how to tell if there’s mold in your air ducts, remember, prevention is better than cure. Keep your vents clear of dirt, dust, and debris with frequent cleaning at least once per 3 to 4 months. Furthermore, ensure any maintenance issues that crop up are handled swiftly.

Besides disrupting your home, mold can be hazardous to your health. Don’t turn a blind eye if you suspect that ductwork has a mold infestation or you have dirty air ducts in general. Having an air duct cleaning service professionally clean your dirty air ducts will ensure the air quality on your home is up to par, particularly if you’re susceptible to allergies.

Frequently Asked Questions

Which mold types hang out in your air ducts?

Some of the more common mold types you have hanging out in your air ducts include acremonium, Alternaria, Aspergillus, Chaetomium, fusarium, mucor, Stachybotrys chartarum, Trichoderma, and ulocladium. No matter what kind of mold you have in your air ducts and HVAC system, it is important you identify it and remove it.

What does an air duct cleaning service involve?

An air duct cleaning service is when you have the various heating, and cooling system components of your forced air HVAC system cleaned. This includes the supply and return ducts, registers, diffusers, heat exchangers, condensate drain pans, fan motor, fan housing, and more.

Once your air ducts are nice and clean, how can you prevent mold in the future?

Once your air ducts have been cleaned, you need to keep up with regular maintenance to prevent mold in the future. Replace the HVAC system filters, reduce condensation within the ducts by insulating them, clean your drip pans regularly, seal any condensation and leaks, and purchase a good dehumidifier and use it in areas more prone to mold growth.