Why are air filters and UVGI light not enough?
Air filters, including High Efficiency Particulate Air (HEPA) filters have been used for many years in heating, ventilating, and air conditioning (HVAC) systems. Some are very effective in trapping particles like pollen and dust. Unfortunately they cannot trap minute particles like viruses, most bacteria, and mold spores that breed in the dark moist interiors of HVAC cooling coils and drain pans, which are located downstream of filters. There is also a problem with fungal spores growing and multiplying in damp HEPA filter material. When this happens, the filter can actually increase the number of spores in the room or the building. Ultraviolet germicidal devices radiate powerful UVC light onto the coils and drain pans inside the air-conditioning system where mold and other odor and disease causing organisms breed. The UVC light inactivates and gradually vaporizes this microbial growth on the coils. In the air stream at 500 fpm it simply does not have enough dwell time to inactivate all
