# Paying less for clean air **URL:** \ **Category:** Factual Questions\ **Created:** [December 4, 2001, 3:40pm UTC](https://boards.straightdope.com/t/paying-less-for-clean-air/96841 "2001-12-04T15:40:30Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Aceospades](https://avatars.discourse-cdn.com/v4/letter/a/848f3c/32.png) [@Aceospades](https://boards.straightdope.com/u/Aceospades)\ **Post date:** [December 4, 2001, 3:40pm UTC](https://boards.straightdope.com/t/paying-less-for-clean-air/96841/1 "2001-12-04T15:40:30Z")
I see on ebay all the time UV air purifiers selling for over $150 and up. These are the type that attach to your ductwork in you ac unit. They just seem to be UV light bulbs that are left on all the time. I’ve seen UV (black light) bulbs in Spencer’s Gifts for A LOT LESS then these purifiers. Are there different types of UV light (one that kills germs and spores and one that doesn’t) or could I just slap one of these bulbs from Spencer’s Gifts into my ductwork and get the same results? ---
**Author:** ![Engineer\_Don](https://avatars.discourse-cdn.com/v4/letter/e/e95f7d/32.png) [@Engineer\_Don](https://boards.straightdope.com/u/Engineer_Don)\ **Post date:** [December 4, 2001, 5:19pm UTC](https://boards.straightdope.com/t/paying-less-for-clean-air/96841/2 "2001-12-04T17:19:46Z")
The UV system are designed to kill bacteria and viruses in the air stream. A well designed system would ensure that that all the air passed a certain minimum distance from the certain intensity bulbs and probably is exposed to the UV light for a certain amount of time. If you know the intensity of the bulbs and the other design parameters you could probably design a system. You could also just put the bulb in a lamp near you and hope it works that way. Personally I think the UV is a waste of time, and a high quality HEPA filter will do just as well or better. ---
**Author:** ![psychomonkey](https://avatars.discourse-cdn.com/v4/letter/p/dec6dc/32.png) [@psychomonkey](https://boards.straightdope.com/u/psychomonkey)\ **Post date:** [December 5, 2001, 1:52pm UTC](https://boards.straightdope.com/t/paying-less-for-clean-air/96841/3 "2001-12-05T13:52:58Z")
The bulbs from spencer’s are a completey different thing, and will not help at all. Edmund Scientific has the thing you’re looking for, just look on their website. -PSM ---
**Author:** ![Aceospades](https://avatars.discourse-cdn.com/v4/letter/a/848f3c/32.png) [@Aceospades](https://boards.straightdope.com/u/Aceospades)\ **Post date:** [December 5, 2001, 3:36pm UTC](https://boards.straightdope.com/t/paying-less-for-clean-air/96841/4 "2001-12-05T15:36:40Z")
What kind of bulb am I looking for? I tried Edmund Scientific web site but it seems to be down. Any other place that I could find it? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [December 5, 2001, 5:14pm UTC](https://boards.straightdope.com/t/paying-less-for-clean-air/96841/5 "2001-12-05T17:14:58Z")
You are looking for a [Gemicidal lamp.](http://www.google.com/search?q=%22germicidal+lamp%22) Take a look at the thread [How do Black-Lights work?](http://boards.straightdope.com/sdmb/showthread.php?threadid=98063) for some more information on the various types of UV lamps. ---
**Author:** ![Aceospades](https://avatars.discourse-cdn.com/v4/letter/a/848f3c/32.png) [@Aceospades](https://boards.straightdope.com/u/Aceospades)\ **Post date:** [December 6, 2001, 3:37pm UTC](https://boards.straightdope.com/t/paying-less-for-clean-air/96841/6 "2001-12-06T15:37:15Z")
I found a lot of info on Germicidal lamps. Basically there UV-C bulbs. My question is still the same. Could I buy a UV-C bulb and stick it into my ductwork (with an electric cord and connecters) and get the same results as these “air purification systems” I see for sale on ebay? Or is there something to these systems that I don’t see that makes them so expensive? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [December 6, 2001, 5:07pm UTC](https://boards.straightdope.com/t/paying-less-for-clean-air/96841/7 "2001-12-06T17:07:57Z")
Yes, as long as you get ~the same intensity bulb to handle the same airflow. It might be more expensive than you think to build yourself a good relable system though. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [December 6, 2001, 5:11pm UTC](https://boards.straightdope.com/t/paying-less-for-clean-air/96841/8 "2001-12-06T17:11:34Z")
Sort of in the same way that a spellchecker is more **reliable** than a quick glance for finding typos.