SPT SU-9210 Digital Evaporative Humidifier Enjoy a comfortable living space with this cool-air evaporative humidifier. This technology is effective and low-maintenance: unit draws dry air in and it is passed through a moisture-laden wick filter (which retains the minerals and deposits in the water), then pushes and circulates the moist air throughout the room. The digital humidistat allows for precise humidity control or set it to continuous for maximum humidification.