Mold in Ducts: Detection and Removal

This may contain: an air conditioner in the corner of a room with moldy paint on it

Mold is a part of the natural world. It serves a valuable purpose in breaking down organic matter, however, that doesn’t mean you have to live with it indoors. This fungus looks unsightly and causes musty odors as well. It also creates poor indoor air quality and prevents the HVAC system from running properly. Mold in ducts threatens the safety of building occupants but WTI | Pure Air Control Services removes mold to create a healthier indoor environment.

Mold in Ducts

A mold is a form of fungus made up of microscopic organisms. It exists everywhere. Mold spores are often safe in small quantities, but if they come into contact with humid and damp areas of buildings, they grow and spread. Once discharged into the air, spores get brought into the lungs where they cause irritation. Spores also settle on surfaces where they get disturbed and reenter the air.

Mold produces mycotoxins and microbial volatile organic compounds (MVOCs). While some molds are harmless, many are hazardous to humans. Mold in ducts releases spores that spread throughout the building. This poses a risk to young children, the elderly, and people with preexisting diseases.

Some of the mold strains that grow in HVAC ductwork include:

  • Mucor Mold
  • Acremonium Mold
  • Alternaria Mold
  • Aspergillus Mold
  • Stachybotrys Mold
  • Fusarium Mold
  • Ulocladium Mold

Detecting Mold in Ducts

Several telltale signs alert building managers to a mold problem indoors.


A musty odor is a good way to detect mold in ducts. This rotten or stale smell vanishes while the HVAC system operates, but returns when the system is idle.


Mold spores are so tiny you won’t see them floating through the air. However, mold colonies are easier to spot. Look for discolored areas in basements and crawl spaces. Mold thrives in damp areas such as underneath sinks and around showers. Water intrusion provides an ideal spot as well. This can occur around windows, wallboards, and cracks in the foundation.

Look for signs of mold around AC vents, in the ducts, but also in drip pans. Check condenser coils as the coils remove moisture from the air which collects in drip pans. If the pans become clogged this then creates the perfect environment for mold growth.

Health Symptoms

Even if you can’t see or smell mold in ducts, it can trigger allergy symptoms such as nose and throat irritation, headaches, itchy eyes, and nausea. These symptoms in the workplace lead to a loss of productivity and more missed work days. Long-term exposure may lead to more serious respiratory illnesses.

WTI | Pure Air Control Solutions to Mold in Ducts

WTI | Pure Air Control Services uses proven methods to detect, clean, and disinfect HVAC systems. Further, our around-the-clock IAQ monitoring services react to IAQ threats as they arise. This helps facilities managers keep their buildings safe, but also their occupants.

Building Sciences

Our building sciences provide affordable indoor environmental testing based on HVAC zones. The lab at WTI uses photographic evidence as well as air and surface samples to detect germs, particles, and mold in ducts. In addition to mold detection, the lab also conducts the following:

  • Allergen and dust screening
  • Test and balance reporting
  • Wall and floor moisture testing
  • Infrared thermography
  • Contaminant source and risk assessments
  • Logging of temperature and humidity levels

The building sciences suite of the methods also includes an HVAC assessment that gives building managers an accurate look at the effect of the system on IAQ. As well, our real-time monitoring program, IAQ Guard 2.0, uses building sensors to monitor and record particular IAQ metrics for our technicians to review.

Hygienic Duct Cleaning

Our hygienic duct cleaning services include four methods to disinfect and restore ductwork. This includes the PURE-Duct method to dislodge built-up dirt and debris and remove it. Next, PURE-Steam disinfects the unit and eliminates any bacteria, mold, or yeast t


hat may still be present in the indoor environment. The third method, PURE-Decon, is a complete, comprehensive room disinfection service. The last step is the replacement of decaying fiberglass insulation with PURE-Cell insulation. This fiberglass-free material is safe and energy efficient.

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