The truth about UV lights in your HVAC systems.. UV lights placed by the air handler can disinfect the air passing through, killing many airborne mold spores and helping prevent new mold from forming on coils, drain pans, and duct surfaces. They’re a good preventative tool to keep HVAC components cleaner and improve indoor air quality. But UV won’t remove existing mold growth—it can inactivate spores on exposed surfaces but won’t clean or remove mold already embedded in materials. Also, do not i