Unlike air conditioners, evaporative coolers add moisture to the air rather than remove it. This is very useful in dry climates, however, it is not recommended in humid climates. They also provide constant fresh air to the house rather than recirculating the same air. They require a window to be open slightly to allow the warmer air to escape out of the house.
Swamp Cooler, Desert Cooler, Wet Air Cooler
Evaporative coolers cost half as much to install and 1/4 as much to run as air conditioners. Their cost ranges from $360 for a window unit to $940 for a whole house unit that cools up to 1,100 sq. ft. They do however require much more frequent maintenance, and as many evaporative cooling units are located on the roof, this means it will be necessary to go on the roof to do the maintenance.
Costs vary greatly by region (and even by zip code). To get free estimates from local contractors, please indicate yours.