When my family moved to the San Fernando Valley in the late 1950s, most homes came outfitted with evaporative swamp coolers. I remember that they worked fairly well until August and September when temperatures soared over 90 degrees. Then, it seemed, all that the cooler did was burn energy pumping water around the pads while we roasted inside our home.
Evaporative coolers were first used in this country in the early 20th Century to cool engines and manufacturing equipment. Water was pumped onto wool pads that encircled a fan blower. The still predominate modest homes in the American Southwest, where temperatures are hot and humidity is low. They won't provide much relief in high-humidity locales.
Evaporative coolers vs. air conditioners
The U.S. Department of Energy says that swamp coolers replace hot interior air with fresh air that can be cooled by as much as 40 degrees before streaming into the home. The coolers cost half the installation charges as modern HVAC units and require an eighth of the energy to operate.
Your swamp cooler is either installed as a down-flow unit from the roof of the house, connecting it to a duct system. For safety against flooding or leaks on the roof, installers recommend installing them on pads set on solid ground.
Fall maintenance for swamp coolers
Simple Technical Solutions has a video online that shows routine maintenance procedures for your swamp cooler. During the hot summer months, I would always climb on the roof and replace dried-out pads and inspect the belts. You should replace them if there's more than an inch of play. In the fall, we would put our swamp cooler to bed for the winter.
Perfect Home HVAC Design suggests that you use Lime-Away or simple household vinegar in the fall to dissolve any hard water deposits that have collected over the summer. The deposits can clog the feeder tubes so only one or two pads are moistened. Then it takes more energy for the cooler to operate while providing significantly less cooling.
The next winterizing step is to turn off the water supply at the source and drain all the lines and remove the overflow plug so the remaining water fully empties from the reservoir. You'll be disappointed come spring if you find a water line that has burst from freezing.
Last, put a cover over the unit to keep warm interior air from seeping out of your home during winter months.