Have been 3 thereof. In the office, kitchen and rumpus room. The air purifier is super easy to use (on and ready) Since I use these things linger even my most militant Non smoking in my room without at minus 10 degrees, the windows tear. The ceilings are in my opinion also no longer yellow. In the party room, the walls smell (are made of carpet) not nearly more smoke. The filter should suck every 3 months with a vacuum cleaner (instrument displays the automatically) Then you see something first of all fields so. Dust, cat hair, etc. In addition to the aspect of health, this device will save significantly on heating costs and painter! Since I do not have any allergies, I can not pass judgment on the pollen filter, but think that this device really all einschnüffelt and cleans.