We have two of the Blueair 211+ units. They work very well and seem efficient. If you notice an odor in the room just switch it up a notch and it takes care of the problem. During the California wildfires our inside air quality was very good because of the Blueair. We have them running 24/7 so the filters need replacement fairly often, which can add up, but well worth it. Filter replacement is super simple. Highly recommend!