Swordfish Air can be installed in both return and supply ducts. Installing the unit on the return duct will provide a higher residency time (longer path for the air to be exposed with the radiation), which results in a better air purification application. Installing the unit on the supply duct and on top of the AC coil will provide surface disinfection for the AC coil for mold prevention, as well as air purification with a lower residency time (compared with return duct installation).