We received this purifier as a gift on Christmas 2010. My wife had recently quit smoking & suffered from frequent bronchial & sinus infections. We live in an older dusty house which didn't help. We had upgraded our whole-house filter to a higher MERV rating so I had reservations as to how much this unit would help. It works great and you wouldn't believe the amount trapped in the filter! My only complaint has been locating filters till I found a website carrying both our whole-house & this devices filter media at reasonable prices.
My husband had been practically begging for us to get an air purifier. I purchased this purifier at a steal for more than 75% off from Target. I couldn't pass up the opportunity or the deal. It is really quiet on low and medium. When it is on high you it reminds you of a fan blowing on high. I could definitely feel the air moving in the room about 30 seconds of turning it on. The replacement filters are inexpensive,especially when purchased in bulk. The manual states they should be replaced at max every 3 months. There is also a filter indicator that lets you know when it should be replaced.The unit is large but not an eye sore as compared to other filters. It's weird because I have it on now and I can feel the air moving but can't hear a thing. My family suffers from severe allergies so this was kind of a no-brainer. I would definitely recommend this unit.