A repair guy was selling me on a new furnace today, and one of the options was a fancy filter system. Instead of the usual air filter, there is a filter with a big UV light behind it like this one. The idea is that the UV light will kill germs and allergens so that they aren't sent through the central heating system. They claim:

ULTRA-VIOLET LIGHT TECHNOLOGY is a proven, economical, and effective means of controlling Microbial Pathogens. Pathogens are sub-micron organisms that fall in the Fungal, Bacterial and Viral categories. They are too small to be captured by standard filtration methods.

Does putting a UV light in the ductwork like that work?

  • 4
    And how would you kill allergens? Few are alive in the first place! Sep 29 '15 at 23:00
  • en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation -- "UVGI can be used to disinfect air with prolonged exposure. Disinfection is a function of UV intensity and time. For this reason, it is not as effective on moving air, when the lamp is perpendicular to the flow, as exposure times are dramatically reduced... However, a UV lamp placed at the coils and drain pans of cooling systems will keep microorganisms from forming in these naturally damp places."
    – n00b
    Sep 30 '15 at 1:39
  • @LorenPechtel: Dust mites is the obvious example.
    – Oddthinking
    Sep 30 '15 at 13:30
  • The claim quoted only mentions germs (pathogens), not allergens.
    – GEdgar
    Oct 1 '15 at 12:24

UV lights only destroy germs, bacteria,and helps to prevent illness and disease .. and does not remove most allergies and dust or chemical fumes,gases,or cigarette smoke.

  • 1
    Do you have a source for your claim? Please keep in mind this isn't a typical discussion blog and that answers require solid evidence to accompany them. As it stands, you answer is not good enough, unfortunately.
    – user28632
    Oct 1 '15 at 6:11
  • 1
    From my understanding, this answer is technically correct. But the nature of Skeptics requires sources and evidence. Editing your answer will result in upvotes rather than downvotes.
    – Coomie
    Oct 1 '15 at 8:53

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