Why would you put something called a swamp cooler in your home? Evaporative coolers are sometimes the answer for people who do not have access to a traditional air conditioner or who are looking to save money on their cooling costs. It is a good news/bad news scenario, however, because these products are not air conditioning units. Learn more about the technology involved before buying an evaporative cooler.
What is an Evaporative Cooler?
An evaporative cooler is a freestanding unit that can lower the ambient temperature in a room by between 15 to 40 percent, according to the U.S. Department of Energy. They use evaporation to increase the humidity and cool the air in the process.
In regions that have naturally high humidity, an evaporative cooler is not that effective. The air is already saturated with water, so there is little to gain by adding more humidity to it.
How does the Swamp Cooler Work?
A motor pumps water into pads. Hot, dry air passes through the pads and the water evaporates into it. Evaporation is the vaporization of liquid into gas, a molecular process that burns energy. In a swamp cooler that energy comes from the heat in the air. It pulls heat from the air to fuel the evaporation and the air cools as a result.
Air can only carry so much of water vapor, though. This is why swamp coolers do not work well in places where the humidity is high. If the air is humid, it is already saturated with water, so evaporation will not occur when the air passes through the wet pads. The unit will simply recirculate the same hot, humid air.
How is that Different from Traditional Air Conditioners?
The California Energy Commission explains that air conditioning units use a refrigerant chemical that converts from gas to liquid and back again as part of the process. The chemical sits in a closed-system of coils. As it changes back and forth from liquid to gas, it pulls heat in for energy.
A fan blows hot air in the home over the coils. The refrigerant pulls the heat from the air to fuel its conversion from liquid to gas. A second fan blows the cold air back out to cool the space.
The basic principle behind these two forms of cooling is similar. They both rely on evaporation to pull heat from the air. The difference is an air conditioning unit is not influenced by the humidity. An air conditioner uses a chemical to cool the air, not water, so humidity is not a factor.
Advantages of an Evaporative Cooler
An evaporative cooler is less expensive to run. Alternative Heating Info reports a swamp cooler uses a third of the energy. Evaporative coolers are freestanding units, too, so no installation costs or air conditioning repair expense.
The Drawbacks of an Evaporative Cooler
The downside of an evaporative cooler is the humidity factor. If you live in an area with high humidity, such as a tropical environment like Florida, this type cooler is of little use. It can help in areas with mixed or low humidity only.
USA Today states that at 50 percent humidity, a swamp cooler will lower the temperature by 10 degrees. If the humidity is only 10 percent, expect a drop in temperature of 20 to 30 degrees.
Can an evaporative cooler replace an air conditioning unit? For most of the country, probably not, air conditioning is almost always the better cooler. A heavy rain is enough to render the evaporative cooler ineffective. Check with your local weather service to see what the average relative humidity is in your area before investing in a swamp cooler. Check out sites like http://www.capefearair.com for more information.