This genuine Aprilaire replacement water panel is the backbone of your Aprilaire humidifier. The heavy-duty aluminum mesh frame holds its shape over the life of the water panel as the porous ceramic-type coating absorbs water and maintains the proper level of hydration to support the evaporation process. Water is vaporized as air warmed by the furnace passes over the water panel. The humidified air is carried through the house through the air ducts. Water Panel Evaporators are the heart of your humidifier and the component which generates the important humidity to keep you comfortable during the heating season. The water panel slides into the scale control insert and the water distribution tray sits across the top of the panel.