The Honeywell HCM-350 cool mist humidifier has a 1.1 gallon water tank and can efficiently humidify an area of between 500 and 800 square feet. It kills up to 99.9% of mold, bacteria and spores in the water before creating the mist. Quiet operation with 3 different fan speed settings make it ideal for your little ones nursery. On a single water tank refill, it can work for up to a maximum of 24 hoursh with a maximum output capacity of 2 gallons per day. Tank can be removed for easy maintenance. It has a small footprint for easy transport and storage.