Can the coils of heat pump units develop a fungal infection?

In homes with heat pump units that are not equipped with ultraviolet C (UVC) lights, the heat pumps often emit odors that can be unpleasant to residents who use heat pumps. These residents may not realize that these odors come from fungus, mold, and bacteria that have collected on the coils of the heat pump units.

When not controlled by UVC, fungus, molds, and bacteria from heat pump units can spread throughout HVAC ducts. In addition to emitting unpleasant smells, they can create health problems, cause a reduction in heat pump efficiency, and an increase in energy consumption.