The HoMedics Top Fill Cool Mist Ultrasonic Humidifier. Breathe easier, sleep better. Ultrasonic, high-frequency technology converts water into a cool, fine mist that effectively adds moisture to the air. The easy-to-fill, easy-to-clean, top-fill tank holds 1.47 gallons of water, offers a runtime of up to 70 hours, offers whisper-quiet technology, and is ideal for family rooms and bedrooms up to 426 sq. ft.*. With all its bells and whistles, the Total Comfort Deluxe is a great addition to any home.