I received this purifier around two weeks ago and so far I am very impressed. First of all, it is really an attractive unit obviously will built. Secondly it is very quiet, not only on low speed, but on the high-speed even turbo as well. I have never had an air purifier and I’ve had some very nice ones that is this quite. As far as the functionality , It is a very sensitive unit meaning that it will change colors when detecting for an example cooking odors and will eventually return to the lower level of air impurities or odors by color reducing accordingly on the indicator. I am Very pleased with the performance of the unit and the air quality is actually better I have three dogs and believe me pet dander is an issue. I would recommend this unit to anyone who is serious about having cleaner air in their home.