An evaporative cooler, also called a swamp cooler, is a device that cools air by evaporating water. As the water evaporates, it absorbs heat from the air, making the air cooler.
Evaporative coolers work best in hot, dry climates. They are much less effective in humid climates because the air is already saturated with water and there is not much room for the water to evaporate and absorb heat.
Evaporative coolers are not as effective as air conditioners at cooling a room, but they are much less expensive to purchase and operate.
If you live in a hot, dry climate and are looking for a low-cost way to cool your home, an evaporative cooler may be a good option for you.