To anyone thinking of buying this, think twice if noise level is an issue for you. I was looking forward to using this air purifier based on all the positive Amazon reviews, but it turns out the fan is WAY too loud for use in my house. The lowest setting was clearly audible from two rooms away. I thought for a moment that the default power-on fan setting must be the highest speed, but no–it only got louder! I returned it to Woot immediately.
Maybe I got a defective unit, or maybe this really isn’t as good as all the reviews say. Either way, the one I got was way too loud to use on a regular basis. Might be good as a white noise machine by your bed, but not recommended for anywhere people are talking, watching tv/movies, listening to music, etc. Noise level is simply too intrusive.