Acu-Steam Steam Humidifiers are another quality product by Thermolec, an industry leader in comfort heating products. Its compact size and standard features make it the easiest to install, operate and maintain. Available capacities from 4.8-12.8 lb/hr (2.2-5.9) kg/hr) in On/Off operation or optional modulating controls. Thermolec's Acu-Steam is the most dependable and easiest to maintain steam humidifier available.