The QuietClean tower air purifier offers superior air cleaning power with permanent filtration. The high efficiency permanent filter removes up to 99% of airborne particles such as dust, pollen, smoke and pet dander, returning cleaner, fresher air to your room. Compared to ionic air purifiers, the filter from the HFD-110 captures 12 times more pollutants . A powerful but quiet fan pulls air into the unit, circulating and filtering the air in your room several times each hour. The permanent filter is easily rinsed clean in water, requiring little maintenance and no expensive replacement filter costs. An automatic filter clean indicator will even remind you when it's time to clean the filter. Easy-to-use, touch button electronic controls allow you to choose from 3 air cleaning levels. You can also set the timer to automatically shut the air purifier off after 4, 8, or 12 hours. The convenient tower design takes up little space, making it ideal for any room in your home.