For large rooms up to 220 square feet, this air purifier features electronic controls and 3 fan speeds, including Sleep Mode for quiet operation while saving energy (Energy Star Certified). The True HEPA filter captures 99.97% of particles as small as 0.3 microns. Removes airborne allergens such as dust, pet dander, pollen, tobacco smoke, fabric fibers and mold spores. A Whishield™ anti-bacteria activated Charcoal pre-filter traps odors and pre-cleans the air before it reaches the HEPA filter. Whishield™ anti-bacteria technology inhibits the outgrowth of micro-organisms on the pre-filter, eliminates over 99.99% of germs and bacteria and stops the secondary downstream contamination to occur on the pre-filter. The Whispure™ Quiet System offers the quietest high efficiency air purifier technology*.