Evaporative Coolers

Have you ever noticed how cool it feels near a waterfall on a hot summer day? That's evaporative cooling: the reduction in air temperature that occurs when water evaporates. Evaporative coolers, commonly called "swamp coolers," use this effect to cool areas. Evaporative coolers have a low first cost, use a lot less electricity than conventional air conditioners, and do not use refrigerants, such as chlorofluorcarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), that can harm the ozone layer.