While air conditioners can greatly increase comfort in the middle of summer, they come with a number of disadvantages. An air conditioner works with the same mechanism as a refrigerator, essentially refrigerating the air and then blowing it back into the room. This process takes a lot of energy and can produce very cold air. Every now and then, the coils can ice up from condensation on the coils.
If you live in a dry climate, there is a better option. Evaporative air coolers need just enough electricity to run a pump and a blower, and the only waste from the cooling mechanism itself is water.
How an evaporative air cooler works
An evaporative air cooler-sometimes called a swamp cooler-basically consists of a box lined with synthetic moss or corrugated cellulose sheets. It has a pump that sends water from the top of the box through the corrugated cellulose sheets inside and a blower motor that flows air through the sheets. It's positioned similarly to an air conditioner window unit, with only an open vent that sits in the window of a building; the rest hangs outside the window.
These air coolers work because it takes heat to evaporate water. That is, heat has to come out of the air in order to lend the essential energy to turn the water from a liquid into a gas. The result is air that feels cooler.
Routine evaporative air cooler maintenance
In most cases, the evaporative air cooler will need very little maintenance. Just like an air conditioner, it will probably need to be removed from the window during cold weather. Alternatively, you can leave the cooler in place and put plastic over the window from the inside. Detach the water supply and make sure that the interior of the cooler does not have any standing water.
While the sheets or pads inside a swamp cooler are fairly resilient, they will need to be changed occasionally. Most evaporative air coolers are built with a removable panel or some other way to access the pads. If you start to detect odors from your swamp cooler, most likely the pads need to be changed. Very hard water may also leave buildup on the pads and interior of the cooler, necessitating regular cleaning.
When to choose an evaporative air cooler
Evaporative air coolers are extremely popular in areas that are very hot and dry, such as the Southwestern United States and other very dry states such as Idaho, the Dakotas, Wyoming and Colorado. In these climates, you get the best bang for your buck out of an evaporative cooler. Not only does it cool quickly and efficiently, but it offers some humidity inside buildings that might otherwise have 30 percent or less. In the aforementioned states, it is not abnormal to see relative humidity in the single digits, which can speed dehydration, cause sore throats and increase the incidence of nosebleeds.
Operating costs of an evaporative air cooler are estimated at about 25 percent of an air conditioner costs, and installation costs compared to central cooling are considerably lower. If you live in an area that typically gets over 85 degrees in temperature and has 60 percent or less relative humidity, then you may want to start considering the purchase of an evaporative air cooler. The higher the temperatures get, and/or the lower the relative humidity, the more efficient the evaporative air cooler will be.