Not whisper quiet, and we still get colds, but it does control odor
I've been using this in our laundry room, where the cat box is, for about 2 months. It has definitely reduced the odor in that room (which is 8 x 6 feet). I also put this in our two-car garage for a couple of days, and it did noticeably reduce the smell in there as well.<br /><br />As others have mentioned, the Germ Guardian is not at all "whisper quiet". I suppose it depends what level of noise you are used to, but we live in the country where it is generally silent, and I definitely notice the hum of this. I do not mind it running in the laundry room, but I would not be able to sleep in the same room with it.<br /><br />As for reducing the spread of colds... I wish it worked, but so far in my house it has not. A visitor brought a cold over Christmas and this did not keep us from getting sick. Of course, it was only running in the laundry/cat room. Our house is 1600 square feet, so to clean that much air we would probably need at least six of these. I do not like this enough to buy six of them.<br /><br />Compared to the price and features of other air sanitizers, this is worth a try.
Rating: 4 stars