There are two types of UV lights for HAVC systems.
Coil Sterilization – A “stick type” light installed inside the return air duct near that sterilizes the air handler coil. A coil sterilization UV light runs 24/7 and is the most common type of HVAC UV light. It is also most reasonably priced.
Air Sterilization – A complete UV light unit that sterilizes moving air. The UV light unit is installed in the return air duct and cycles on with the air handler blower. Sanuvox is a top-rated manufacturer of air sterilization systems.