Wet the back of your hand and then blow on it. Your skin surface feels cooler. That’s evaporative cooling.
A swamp cooler or an evaporative cooler, is essentially a box-shaped appliance with porous surfaces that enable air to pass through. The fan inside the swamp cooler pulls outside air through the sides and into the appliance. The fan moves the hot outside air through water-wetted pads, cooling the air about 20-25ºF as the air evaporates water molecules from the pads. The fan then blows the cooled air through the house.
Swamp coolers are popular in dry climates because they are inexpensive, use a quarter as much electricity as an air conditioner of equivalent size, are easy to maintain, and add a comfortable level of humidity to dry air.
To choose the right size evaporative cooler for your home, you need to determine how many cubic feet of air per minute (CFM) the unit can pump.
If you can’t locate the CFM number on your evaporative cooler or in the owner’s manual, the following formula will help you calculate it:
* Multiply the square footage of your home by the average height of the ceiling (in feet).
* Divide by two (air changes per minute).
Example: 1,625 sq. ft. x 8 ft. (ceiling height) = 6,500 CFM/2