Lasko’s 9-gallon recirculating humidifier with digital humidistat is ideal for open floor plans and large living areas up to 3200 square feet. The removable 4.5 gallon water tank with easy-carry handle simplifies fill-ups. The continuous water recirculation self-cleans the filter to maintain high efficiency. Continuous circulation of water through the unit keeps the entire filter moist for maximum evaporative moisture output. You get cool clean invisible moisture without white dust or over-humidification.