Rabbit Air BioGS SPA-421A

Unlike the typical boxy air purifier, Rabbit Air units are slim and modern-looking. They're also very quiet and energy efficient, kicking into high speed only when sensors detect higher levels of air pollutants. The Rabbit Air BioGS SPA-421A (*Est. $330) uses three types of filters -- prefilter, HEPA filter and charcoal -- to capture allergens, odors and chemicals, similar to other high quality air purifiers such as the best-rated Austin Air HealthMate (*Est. $490). However, unlike the HealthMate, Rabbit Air purifiers include an ionizer. Ionizers can emit ozone, a known lung irritant, as a by-product, and the experts recommend avoiding those that emit even small amounts.

Rabbit Air says its ionizers emit no ozone, but we found no independent verification of this claim. Rabbit Air says the BioGS SPA-421A can clean the air in a 600-square-foot room. A pricier model, the Rabbit Air MinusA2 SPA-780A (*Est. $550), offers additional customizable filters and claims to be able to handle an 815-square-foot room. However, Ed Sherbenou at Air-Purifier-Power.com says these units do not appear to have the power to change the air very often in rooms that size. Rabbit Air gets high marks for service from customers, and the Better Business Bureau gives the company its highest rating for reliability.

We found very few reviews for Rabbit Air purifiers, but Sherbenou and users at Amazon.com say they are quite impressed with them. The company's A-plus rating at the Better Business Bureau is also reassuring.