I bought this for the tiny office lobby that I work in and its the perfect size. It operates quietly and efficiently, in that the light changes color to let you know when its having to work a little harder to clean the air. Its unobtrusive, its easy to operate. The one thing that I would change are the instructions, to say WHY is it changing color and how does that affect the air. Just a smidge more explanation would have been super. Upon reading online, I figured it out however. I would buy this again for another room.