UVC lamps are relatively inexpensive to install. Usually they're put before and/or after the cooling coil where, if you have a clean coil, the light will bounce

UVC lamps are relatively inexpensive to install. Usually they're put before and/or after the cooling coil where, if you have a clean coil, the light will bounce through the fins and increase the path length of exposure. If it's not clean, the UVC helps to break down anything organic over time and cleans them up. With a few exceptions of more complex units all of the recirculated air spends time passing through the coil. UVC doesn't damage metal parts, but does effect some materials that would be common in residential installations https://customer.honeywell.com/resources/techlit/TechLitDocuments/50-0000s/50-8788.pdf https://customer.honeywell.com/resources/techlit/TechLitDocu...