Evaporative Coolers work as their name suggests by evaporating water, in addition to cooling the air, these air conditioners also humidify it. Evaporative Cooler units are ideal where a constant supply of fresh outside air is available, e.g. for cooling a Marquee or a large open workshop. Units do not have a fixed cooling capacity as the drop in air temperature over the unit depends upon the temperature and humidity of the air supplied to it. Evaporative Coolers require a constant supply of water that can be introduced manually or, on selected units, automatically via a connected hose.
For: Units move large air volumes. Can be used as fan only.
Against: Units require a constant supply of water. Will not cool in enclosed spaces. Will not cool below the ambient wet bulb temperature.