This air purifier can clean up to a maximum area of 1200 sq. ft.  When I used it in my main living area, the numbers would go up and down to show it was working and cleaning the air. When moved upstairs between 2 bedrooms, it will occasionally go down if the heat goes on or windows are opened. The power it uses is automatically adjusted. Very little hands on maintenance for the owner to use this. It is very quiet, very portable and is slim in design so it can be moved from area to area very quickly. It has an odor guard on that helps to protect the household from cooling, cleaning grass mowing odors etc. a big bonus of this air filter is the filter only needs changing about every six months.