Since 1908, swamp coolers deliver low-energy cooling as heat rises

Cooling is one of the fastest-growing loads on the grid, and as heat waves intensify, climate and energy planners are hunting for efficiency wins. The swamp cooler is a reminder that a 1908 innovation—evaporating water to cool air—can slash energy use compared with vapor-compression AC in dry climates, serving as a low-carbon complement to the electrification push.

Long before vapor-compression air conditioning became the default assumption of American comfort, the arid Southwest leaned on a technology that now reads as surprisingly modern: the evaporative cooler, or "swamp cooler." Two syndicated features published August 21, 2026, by the Times-Standard and The Times-Tribune retrace the device's lineage—from ancient civilizations fanning air over water in clay jars to Oscar Palmer's 1908 refinement in Arizona—and argue that a century-old, low-energy cooling method still matters as the country heats up. The features are part of an "America 250" retrospective, but their real value is forward-looking: they reframe a humble, low-tech appliance as a serious tool for an era of extreme heat and strained power grids.

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In hot, dry climates, evaporative coolers can consume on the order of 50% to 75% less electricity than comparable vapor-compression units—and they avoid high-global-warming-potential refrigerants entirely.

The mechanics are simple and energy-light. A fan pulls fresh, hot outside air through vertical, porous pads saturated with water. As the air passes through, the water evaporates, cooling and humidifying the airstream before it is directed indoors. Unlike vapor-compression systems, which use refrigerants and compressors to move heat, a swamp cooler's primary energy demand is a fan and, in some configurations, a small water pump. That distinction matters enormously in a climate moment defined by rising temperatures, cooling-load growth, and concern about electricity demand.

The historical arc is striking. Palmer's 1908 system gave the concept a commercial American form, and by the 1930s evaporative coolers had spread across New Mexico, Nevada and other southwestern states, changing where and how people could live in desert climates. Standard air conditioning did not become broadly common until the 1950s, and even today central air remains a luxury for many households. The swamp cooler, in other words, was the Southwest's original cooling infrastructure—and it never fully disappeared.

Its modern advocates frame the device in efficiency and equity terms. Eric Verpolegen, founder of CoolVeg, a nonprofit focused on evaporative cooling for fruits and vegetables, notes that in truly dry conditions—"if it's really dry out, in Arizona"—the cooling effect is greatest. Ankit Kalanki, principal of cooling at RMI, a clean-energy nonprofit, positions the technology as an access solution: "Where you don't have air conditioning and where the climate allows, evaporative coolers could be a good solution and are low cost, low energy consumption." Those two attributes—low upfront cost and low operating energy—are precisely what matter for cooling access in hot, dry, lower-income regions.

The technology's ceiling is also well understood. Evaporative coolers and fans underperform in humid climates because the air is already near saturation and cannot absorb much additional moisture; the evaporative process that drives cooling stalls. The features note that experts say humidity has been worsening in some regions, which would erode the swamp cooler's effective geography even as dry-bulb temperatures climb. This is the central tension: the places most in need of cheap cooling are not always the places where evaporative cooling works best.