Air Duct Mold: 3 Steps to Improve HVAC Quality

HVAC air ducts are a common breeding ground for dust, debris, and even rodents! Air duct mold is far more common that one might think. During a recent job, Ben Fetzer, and his crew discovered a major indoor air quality concern. With a newly renovated Mission Hills home.

How HVAC & Air Duct Mold Form

Mold is found everywhere, and with everywhere, we mean absolutely all the places where moisture can be detected. It is common for mold in air ducts. Mold can be growing inside your heating and cooling systems as well. The ductwork, drip pans, and coil evaporators of ACs are the most favorite regions for mold. Ductwork produces condensation in areas of the property where hot and cold air meet.

Most of the time air duct lines run in areas where the temperature is not controlled. Like unfinished basements, garages, and crawl spaces. Which can cause the duct line to have condensation (humidity). Along with the dust and debris in the duct line, it creates the perfect breeding ground for mold. Mold in air ducts is one of the most dangerous and overlooked areas. Allowing to easily penetrate your respiratory system through the air in your system. Mold can also be easily circulated throughout the property; if precautions are not taken during the process of removing molded drywall and materials. Let’s explore some facts about the mold in air ducts, precautions, steps to resolve and prevent.

Why is Breathing Mold in Air Ducts a Concern When it is Found in Nature?

When growing externally, mold presence isn’t dangerous, but in fact, they balance the ecosystem. Mold belongs to the family of fungus and grows inside tiny filaments. They are capable of floating in the air and settling anywhere they can find moisture. Mold is a natural product of nature. That causes things such as wood, leaves, and dust to break down and decompose. In nature, mold releases toxins. However, with the vast air space, the mold spores that you breathe are not as concentrated as an indoor environment. Many fall allergy suffers are reacting to mold in the air. Even with seasonal allergies, the outdoor environment cannot produce a toxic mold level due to the vast air space.

However, indoors where the air is continually being recirculated through the air system; the indoor air environment is limited to a small space; hence toxins produced by mold can easily become a dangerous level. As a result, you get exposed to toxic mold. Which can cause severe health problems and respiratory problems such as asthma and allergies.


How to RESOLVE Mold in Air Ducts?

  1. Go directly to the source of the mold problem. By removing any mold damage in the property by a certified mold professional who will follow EPA guidelines.
  2. Have your ducts and air handler thoroughly cleaned by a professional vent cleaning company; that will put your duct line under negative pressure.
    • It is NOT recommended to use a vent cleaning company that uses a brush. Or blows air through the duct line without negative pressure, as this can cause your problem to become worse.
    • At Fresh Start, depending on the mold removal job, we automatically include cleaning of the duct lines in our estimates.
  3. In addition to cleaning, we recommend fogging the duct lines with an antimicrobial solution. To kill any remaining mold spores in the duct line.

Following these above-mentioned steps is the most effective way to eliminate mold from your indoor air environment.

How to PREVENT Mold in Air Ducts?

  1. Prevent condensation in the duct line by wrapping any air ducts exposed to a temperature change with insulation.
  2. Prevent mold by having any form of water damage remedied by a professional water damage company. Thereby effectively removing all forms of moisture in unseen areas like wall cavities, behind cabinets, etc.
  3. Never remove the mold over 10 square feet, or mold that is located in close proximity to air vents. Without a certified mold professional.

A Fresh Start Story of Mold Removal & Air Duct Cleaning in Local Luxury Home

A customer called last summer. Because her husband had been dealing with health problems. Since moving into the newly renovated luxury home a year and a half ago. There are many differing opinions among mold contractors. In this customer’s situation, the problem was that the majority of the damage was hidden; and not seen to the common person. One mold contractor even told the homeowner to not do anything. Another mold expert advises to do an extensive tear out.

When Ben approached the job he knew he was dealing with two different extremes and rather took a mid-level approach. The customer ended up being really glad she went with him. During the job, Ben and his crew found extensive mold damage and air quality issues within their luxury home. One of the main air quality concerns with the home was the lack of HVAC vent lines in the basement. The vent lines were literal drywall screwed to the bottom of the floor joist. Thereby trapping large amounts of moisture, mold, and dust.

Such a beautifully renovated luxury home in Mission Hills and we are steal dealing with mold problems. It was shocking to see such inferior work covered up and creating such poor indoor air quality. The video below shows Ben discussing the cleaning and sealing that was done. So that new sheet metal HVAC lines could be installed improving the customer’s indoor air quality throughout their entire home.


Posted by Ben Fetzer on Thursday, September 27, 2018

Video Transcription of HVAC Lines Upgrade for Clean Air

Hey everybody. Ben Fetzer with Fresh Start Restoration. Wanted to do a quick video with one little particular point of discussion, that is HVAC returns. This is a residential application. we’ve had mold in a basement and we’ve taken out all the mold. The customer is actually installing brand new HVAC systems, as we speak. Prior to them applying their steel. They’re going to nail a flat piece of steel sheet metal against the bottom of this floor joist. That’s a common practice in residential HVAC applications. This is an air return or a cold air return. But before they did that, I wanted to go ahead and coat all of this wood. That would be sub-floor plank and floor joist.

HVAC Coating

I put an HVAC approved coating, which in this case is IQ 8,000. That’s white. You can get it white or black, but we’ve just sprayed it on there. You can see that it is going to be connected. To this long, this is actually an old piece of aluminum. But that piece of metal right there is going to be the air return that feeds the system. And that system will be servicing the basement and the floor right above the main level.

So, just something to think about when you have these cavities. It’s awesome if you can run a solid steel line. All the way to your system for your cold air returns. But if that’s not practical, it does make sense to coat the wood with HVAC approved coating. So, I’ve got several areas here. I’ll walk over to another one. This is another one here that actually goes up a wall. We’ve put our machine in there and sprayed up in that wall cavity. And it comes over to this section of metal which is then fed over to the main systems.