Generalaire 5144 1042LH Legacy Humidifier 19.2 Gallon Per Day 6" 24V Water is dispersed evenly throughout a Vapor Pad inside the 1042LH. A portion of the heated air from the furnace passes through the water-soaked pad where it absorbs additional moisture and then returns for distribution throughout your home. Newly-moistened and healthier air is provided to you and your family. Features: Replaces 1042L For Home Sizes up to 2,800 Sq. Ft. 17 GPD (Based on 120 Degrees Plenum Temperature) 24V Shut-Off Damper Included: MHX3C Manual-Control Duct Mount Humidistat. Replacement Vapor Pad number 990-13 (GFI #7002). Replace 1-2 times per season. 5 Year Warranty.