Why evaporative cooling? 

Evaporative cooling has gained rapid acceptance because the process relies solely on water evaporation with extremely low energy consumption to produce a significant amount of cooling. Evaporative cooling will generally pay for itself (including installation) in just a few seasons. This equates to a great investment for consumers who on the average own the same home for 5-6 years. Also the low cost of maintaining this equipment is an added advantage to the end user. Evaporative cooling makes sense as add-on equipment to complement existing refrigerated air systems. Installing an evaporative cooler significantly reduces the amount of time that mechanical refrigeration is needed in a given season and the associated higher cost of operation.