Evaporative coolers reduces the air temperature when water evaporates. Evaporative coolers, commonly called “swamp coolers,” use this effect to cool homes and work places. Evaporative coolers have a low first cost, use a lot less electricity than conventional air conditioners, and do not use refrigerants. Have you ever noticed how cool it feels near a waterfall on a hot summer day? It’s the same concept.

Evaporative coolers are sized based on cubic feet per minute (cfm) of airflow. Airflow for evaporative coolers is typically higher than conventional air conditioning systems. Two to three cfm per square foot or three to four cfm per square foot in hot desert climates is typical.

When operating an evaporative cooler, windows are opened part way to allow warm indoor air to escape as it is replaced by cooled air. Unlike central air conditioning systems that recirculate the same air, evaporative coolers provide a steady stream of fresh air into the house.   Control the cooler’s air movement through the house by adjusting window openings. Open the windows or vents on the leeward side of the house to provide 1–2 square feet of opening for each 1,000 cfm of cooling capacity.

TPI 12" Evaporative Cooler