Evaporative coolers are a practical alternative in very dry areas or the budget-conscious. They work by pulling fresh outside air through moist pads where the air is then cooled by evaporation. The cooler air then gets circulated throughout the house. An evaporative cooler can lower the temperature of outside air by as much as 30 degrees.
They could save as much as 75% on cooling costs during the summer due to the fact that the only mechanical component that uses electricity is the fan. Because the technology is simpler, it also costs much less to purchase than a standard central air conditioner.
Central Air Conditioners
Central air conditioners cool the entire house. In each system, a large compressor unit located outside drives the process. An indoor coil filled with refrigerant cools the air that gets distributed throughout the house through ducts. It is a very effective method of cooling the home.