Swamp coolers are also called evaporative coolers. They generally sit on top of a home and function by blowing hot dry outside air over wet dripping pads. As the air enters the home, the water in the dripping pads cools the air. The pads are kept wet with a water pump.
Swamp coolers work best where the air is hot and dry, like in Arizona. In areas where humidity is generally high like Washington DC, Florida or the Dakotas, the swamp coolers don’t work as well because the air is already humid so the dripping pads are less effective at lowering the temperature of the air.
Swamp coolers are relatively inexpensive to operate because they use about ¼ of the electricity that a conventional A/C uses. However, the dripping pads should be changed at least annually and that involves a trip up on the roof. If an area hits a rainy or humid spell, the pads may not properly dry out and start to smell. In that case, they’ll have to be changed as the smell will drift into the home.
Swamp coolers are also known to eventually leak. Since water is constantly cycling through the unit, parts may become rusty and begin leaking. Repairs can be frustrating as it may involve disassembling the unit to find what’s leaking (which is usually the reservoir pan at the bottom).
Why does evaporative cooling work?
Evaporative cooling is essentially wet air traveling through your home or space absorbing heat that’s radiated from all the surfaces. When you first step out of a shower or swimming pool, don’t you feel cool when you first hit the air? That’s natural evaporative cooling.
Swamp coolers are using the same principle. They blow air through cool wet sponges. The blowing wet air picks up heat and makes the space feel cooler. With today’s high energy prices, swamp coolers provide an efficient and cheap process of cooling for people who live in a dry-heat area. In fact, the hotter and dryer the temperature, the better they work. Plus they bring in a constant supply of fresh air. Swamp coolers cost less to buy, and unlike a/c units, can be maintained by the homeowner.