# Air Purifiers: RabbitAir, BlueAir, IQAir- your opinions? experiences? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [May 13, 2010, 3:43pm UTC](https://boards.straightdope.com/t/air-purifiers-rabbitair-blueair-iqair-your-opinions-experiences/539304 "2010-05-13T15:43:51Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![xanthous](https://avatars.discourse-cdn.com/v4/letter/x/53a042/32.png) [@xanthous](https://boards.straightdope.com/u/xanthous)\ **Post date:** [May 13, 2010, 3:43pm UTC](https://boards.straightdope.com/t/air-purifiers-rabbitair-blueair-iqair-your-opinions-experiences/539304/1 "2010-05-13T15:43:51Z")
I’m going to be living in the basement of a friend for a few years. The basement has not leaked when it’s rained hard/often, but she does use a dehumidifier. I have a mold/dust allergy, not severe, but it can be bothersome, so I needs to invest in an air purifier. Of course, I want the best for the cheapest (which includes cost/frequency of filter replacement). Anybody own/use a great HEPA filter they can recommend? ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [May 15, 2010, 3:19am UTC](https://boards.straightdope.com/t/air-purifiers-rabbitair-blueair-iqair-your-opinions-experiences/539304/2 "2010-05-15T03:19:33Z")
I have several AllerAir units that are excellent, but they cost around $800. These devices vary quite a bit in their performance. A good measure of their performance is to multiply the cfm by the efficiency; you can divide the result by the price to see which is the best bargain. This will, by the way, underscore how unimportant the efficiency number usually is. A 99.97% filter will be hard to tell from a 90% filter (though it will take several times more energy and more fan noise to push the air through it).