There’s a Fungus Among Us: Mold and Your Ductwork

There's a Fungus Among Us: Mold and Your Ductwork

Today, we have the pleasure of having Bryan King of Remtech Environmental as a guest blogger. Bryan is a mold expert and he is going to talk to us about mold in our air ducts.

Mold is like that unwanted guest in your home that has overstayed their welcome the minute they arrive. Mold is always present in your home in that it is naturally present in your building environment. If controlled, mold does not present a danger. So what causes mold to get out of control? Moisture.

This summer has been hot and humid in the Raleigh area. With average daily humidity levels at 70% there is a whole lot of moisture lingering in the air. High levels of humidity creates an opportune environment for mold growth.

Mold and Your Ductwork

When moisture builds up in your air ducts dirt and dust particles that would otherwise float right on through get stuck and create a nice cozy home for mold to settle down in. HVAC ductwork is an all to often underestimated and ignored area for mold growth. Have you noticed a musty/mildewy smell in your home? Is there visible mold growth on your vents? If so, your ductwork may be experiencing mold growth.

Causes of Mold Growth in Air Ducts

  • Humidity Levels: when there is excess moisture in the air you can count on that moisture finding its way into your air ducts. While some moisture is unavoidable, excess moisture in your ductwork can cause dirt to cake and create a breeding ground for mold.
  • Leaks Around Duct Joints: this can introduce dirt and spores into your ductwork.
  • Oversized AC Unit: if your AC unit is too big for your house it will not complete the full cycle necessary to remove humidity from the air in your home.


Do it yourself mold removal in ductwork is difficult at best. This is especially true if your vents are insulated, in which case they will need to be totally replaced. Your first step, if you suspect mold growth in your air ducts should be to have them cleaned. If mold growth is found deep with the duct system it may be time for professional remediation.



  •  Invest in a dehumidifier: Consider installing a whole house dehumidifier like the Ultra-Aire Dehumidifier to work with your HVAC unit to combat humidity in your home.
  • Regularly Change Filters: This isn’t like when your dentist tells you to floss and you conveniently forget until roughly a week before your next cleaning appointment. It is critical that you change your air filters every month.
  • Clean Ducts Regularly: Don’t wait for a mold problem to develop to schedule a cleaning and maintenance check-up for your air ducts.

Mold: Get Out and Stay Out

There are of course extreme situations where mold penetrates a home to the point of making its’ occupants sick. However, those cases are the exception rather than the rule. As long as it is remediated properly and controlled, mold is one house guest that you can easily and confidently kick to the curb.