Purifan and Matching Motor Bundle with Allergy Filters (Ivory) Provided approximate 2,200 CFM of filtered air. That is more than 40 air changes per hour for a 20 x 20 foot room. Comes with mounting brackets to install on most 52-inch to 60-inch ceiling fan motors. Quietly filters all the air in the room because it is located in the ideal location in the center of the room, on the ceiling, out of the way, and filters all the air in the room by forcing dirty particle and odor filled air into the Purifan five stage filters. Still moves air proving the celing fan benefits of forcing warm air to the floor in the winter months, and providing wind-chill cooling in summer months, saving energy on your utility bills. Filters are low-cost, disposable, and last a long time. This saves time and requires minimum maintenance during the year. Filters last about 1 year in a home and 6 months in a school, daycare, office or business.