I bought this item to replace another air cleaner that I was using. This unit didn't work correctly from the beginning. It would turn off by itself and wouldn't turn back on until you unplugged it and then hit the sleep button (pushing the "on" button had no effect). It was also EXTREMELY noisy even in "low" mode. I kept it in the very lowest setting as a result which meant it ceirculated very little air and was more or less useless.I lived with it for a few months. Now the timer on the screen indicates the filter needs to be cleaned. After I cleaned the filter, I followed the directions to reset the counter, but pushing the "reset" button doesn't return the screen to show 100% clean filter. After two days of trying the screen still flashes 0% and indicates the filter should be replaced.Now that the unit refuses to turn back on at all, so I guess it is going to the trash can.