Evaporative Coolers

Also known as swamp coolers, Evaporative coolers cool and filter air. Hot outside air is drawn through a water-moistened filter and then blown through a building. To work effectively, windows and/or doors must be left open so this moist air can be exhausted from the building. Evaporative coolers are only effective in drier climates (e.g. like the US Southwest). However, they are significantly more efficient than air conditioners in cooling them home under these conditions.