Which areas of the air handling unit are mostly affected by microbial growth?

The fan chamber of an air handling unit is significantly affected by microbial growth due to its operational environment. It is a space where air is continuously moved, often leading to the deposition of dust, moisture, and organic materials, which serve as a food source for microbes. The increased moisture, due to condensation that can occur in the system, coupled with the organic debris, creates an ideal breeding ground for mold, bacteria, and other microorganisms.

While other areas, such as the filter chamber, return ducts, and condensation reservoir, can also experience microbial growth, the fan chamber is particularly susceptible because of its dynamic nature and exposure to airflow, which can distribute spores and contaminants throughout the ventilation system. The design of the fan chamber can contribute to stagnant conditions, where moisture can accumulate, further promoting growth. By focusing on maintaining the fan chamber, practitioners can reduce the overall risk of microbial contamination in the air handling unit and the broader building environment.