It is extremely efficient. I loved the fact I could use in on the floor but also on a shelf. It has a slick look that depending on how you use it can almost make it not there of if you so desire looks nice as a decoration. Was very quiet and easy to use. In a short time I could till the difference in the air felt light and easier to breath. The only draw back is the filters are a bit pricey. But it would take while before you should need one.