I have a Mountain Breeze Unit, and it really does work, you can tell by the amout of dust it throws againse the walls, makes them a bit mucky, as all the dust is forced from the air. I love mine, really does work, ... If an ionic purifier is labeled as “self cleaning” or “never requires cleaning”, that will tell you it doesn't work very well. The whole idea of ionic purifiers is to collect airborne stuff. I swear by forced air, but some people would disagree......