Best for a Big Room
Air-O-Swiss Digital Warm & Cool Mist Ultrasonic U650
Set the desired humidity level and this powerhouse takes care of the rest, pausing and restarting when needed. A huge tank, more than double those of other full-size winners, handles up to 650 square feet. Dual heads. Height: 14 inches.
To buy: $240, bedbathandbeyond.com.