Initially, it is a little hard to know if it is actually doing something. For example, when I first set it up it indicated that the air quality was 100%. My house is not immaculate, so I had thought it would have to filter the air at least a little bit. It was not until a few days later when we were cooking something in the oven when the purifier kicked on and showed the quality get down to 65% and then it ran until the quality was back to 100%.