Unit is fine. I just have to trust it is working because I can't really tell. Of the 3 settings 1 and 2 are pretty quiet which is good for the bedroom. #3 Is pretty loud so works for a busy living room with kids and a dog coming and going. We use it in a townhouse living/ kitchen area. My 5 year old figured out the buttons pretty quickly, so user friendly. No 5 stars just cause I have no proof it's actually working (the air is being cleaned). That being did my 5 year old loves sticking his face in the fresh air output vent!