The EVAP40 Evaporative Whole Room Humidifier creates acomfortable, perfectly humidified living space quickly andquietly. Vornado's deep pitched blades pull large volumesof harsh, dry air through the unit, and then, using Vornado'ssignature Vortex Action, circulates the humidified airthroughout the room, providing complete and uniformhumidification in spaces up to 900 sq. ft.The EVAP40delivers automatic humidity control with a built-inhumidistat. An easy-to-use control panel allows you tochoose your desired humidity level and fan setting (low,medium, or high). Its extra-large 4 gallon capacity provides4 gallon output every 24 hours when operated continuouslyon high, allowing for long, uninterrupted operation andfewer refills. Includes two durable water tanks that areeasy-to-fill, spill-proof & leak-free. 5 year limited warranty.