Evaporative Coolers Conserve Energy and Save Money

Evaporative coolers (also called swamp coolers) provide energy efficient cooling for the warm, dry climates of the Western States. The lower your summertime humidity, the more successfully that an energy efficient evaporative cooler can cool your home.

Evaporative coolers use only18 to 25 percent of the energy consumed by air conditioners, and evaporative coolers cost about half as much as air conditioners to install. Evaporative coolers compare in performance to air conditioners with a Seasonal Energy Efficiency Ratio (SEER) of between 30 and 40. The most efficient air conditioners have a SEER rating of about 12.

Evaporative coolers have large fans that move air through water-saturated pads. These absorbent pads are made of aspen wood fibers, glass fibers, or specially formulated paper. A water pump in the reservoir pushes water through tubes into a drip trough, which then drips water onto the pads. The water in the pads evaporates, reducing the temperature of the incoming outdoor air. As cooler air is forced into the house, it pushes warmer air out through open windows or through specialized vents called up-ducts. Unlike central air conditioning systems, which are most efficient when your home is sealed up, evaporative coolers provide a steady stream of fresh air to the home.

On cool nights an evaporative cooler can cool your house without using any water, by using a fan-only control setting.

An added benefit of evaporative cooling is that it works best in the hottest time of the day. When the outside temperature increases, the humidity normally drops. In the early morning, for example, the temperature may be 70 degrees, with a relative humidity of 60 percent. By mid-afternoon, when the temperature has climbed to 90 degrees, the humidity may well have dropped to 30 percent. These dry conditions help evaporative coolers work more energy efficiently.