this is a great air purifier, but there are some minor issues. First, the air quality sensor seems to lose calibration every so often will need to be unplugged to reset it. Two, it won't stay on the highest setting, which is a bizarre choice. It'll stay on 3, but if you set it to 4 it'll turn itself off after an hour and I haven't managed to find any way to circumvent this. In a house where every other family member smokes like their lives depend on, not being able to run it on it's highest setting while I sleep is a major downside. Third: smoke. It isn't capable of fully removing cigarette smoke from the air, not when it comes to smell nor the particulates. But to be fair I have an extremely powerful sense of smell and I don't think there's ANYTHING that can effectively fight smoke levels equal to a 1920s smokers lounge.Final verdict: if you're buying it to clean your air it's a great buy. If you want it to remove tons of toxic fumes, not so much. Read more