Alen A350

February 2009. In tests, the Alen A350 air purifier has been shown to remove nearly as many allergens from the air as the more expensive IQAir HealthPro (*est. $750), and it's also a little quieter. Bear in mind, though, that the Alen A350 is meant to cover a smaller area -- 400 to 800 square feet vs. the HealthPro's specified 1,000 square feet -- and one expert recommends its use in rooms of about 250 square feet. Like the HealthPro, the Alen air purifier uses a three-in-one true HEPA filter along with a pre-filter and a carbon filter, and its $40 replacement filters are a lot less expensive. Overall, testers say the Alen A350 is a high-quality air purifier.

We found a good comparative review of the Alen A350 at Air-Purifiers-America.com, one of the few sources that tests air purifiers. The A350 is also included in a brief roundup by Reviewboard.com, receives a handful of posts from owners at sites like Epinions.com and Amazon.com, and is the subject of an in-depth review by the enthusiast site Air-Purifier-Power.com. It hasn't yet been tested by Consumer Reports, however.