How They Work
Generally, air humidifiers have a bypass flow-through style that uses a pipe to bring water directly to an electrically controlled valve at the top of the humidifier. Air passes through an aluminum pad (often called a biscuit; the term “biscuit” emphasizes the solid rather than foamy form). The pad has a coating of ceramic, resulting in an extremely large surface area within a small space. When the humidistat calls for humidity, the valve is opened and causes a spray of water onto the pad. Hot air is passed through the pad, causing the water to evaporate from the pad and be carried into the building.