The Vornado AC500 Whole Room Air Purifier uses true HEPA filtration, one of the most effective filters available, to remove up to 99.97% of airborne allergens down to 0.3 microns in size. The Vornado Whole Room Purifier actively circulates and filters all the air throughout a room. The AC500 uses a radial blower to intake and clean all the air in the room- up to 335 sq. ft. Precision engineering allows the blower to operate quietly, despite it's powerful air flow. A combination of HEPA and carbon filtration to trap Dust, Pollen, Pet Dander, Smoke, Bacteria, Mold Spores, Dust Mites and more. The carbon prefilter both adsorbs odors and traps larger particles. Features 4 speeds, push button electronic controls, filter replacement indicator and industry leading 5 year limited warranty.