Blueair features a patented HEPASILENT filtering technology with advanced media for complete air purification. Its outstanding performance traps 99.97% of particulates at 0.1 microns and cleans and changes the air in a room every ten minutes. It is the quietest and the most energy efficient air purifier available. Durably constructed of galvanized steel and lightweight. Removes dust allergens, animal dander, pollen and all other airborne particles. Also eliminates bacteria, viruses and mold. Each unit comes complete with HEPASILENT filters that last an average of 12 months. Ten-year factory warranty - the industry's best.