Shop for Heating, Venting & Cooling at The Home Depot. The pureguardian 14-Hour Ultrasonic Table Top Humidifier is a cool mist humidifier. Silver Clean technology is used to fight the growth of mold and mildew on the surface of the water tank- a common problem with traditional humidifiers. Thanks to ultrasonic technology it is ultra-quiet when it runs making it ideal to have on while you sleep. It s small and compact and stands at under 9 in. tall, the perfect size for bedside, travel, a desktop, or a child s or baby s room. It weighs just 1.25 lbs., features a 0.21 gal. tank capacity, and runs continuously for up to 14-hours. And with no evaporating pads, wicks or filters to clean or replace, there are no additional costs. 3-year limited warranty.