Let Mold and Bacteria See the Light! No matter how much you clean and disinfect, bacteria, mold and germs still blow through the air in your home every time your heating and cooling system turns on. Plus your air conditioner's moist cooling coil can serve as an ideal breeding ground for mold. Ultraviolet treatment systems act as an additional line of defense to help protect your family. The Honeywell TrueUV system kills up to 99.9% of mold and 87% of bacteria before they can get to your family.