An evaporative cooler, also known as a swamp cooler, is a type of air conditioner that uses the process of evaporation to cool the air. It works by drawing hot, dry air through a wet pad or series of wet pads, which are kept moist by a continuous supply of water. As the air passes through the wet pads, some of the water evaporates and cools the air. The cooled air is then circulated into the room or area being cooled.
Evaporative coolers are most effective in hot, dry climates, where the air is dry enough for the evaporation process to work efficiently. They are a less expensive alternative to traditional air conditioning systems, but they are not as effective at cooling in humid environments, as the air is already saturated with moisture and cannot hold as much heat.