1908 Swamp Cooler Still Cuts Cooling Energy Demand in Arid Climates

As climate change drives up cooling demand and strains electricity grids, a 1908 technology is getting renewed attention from energy analysts. Evaporative or 'swamp' coolers use water-saturated pads instead of refrigerant compressors, dramatically cutting energy consumption in dry climates. For climate and energy professionals, the question is whether this low-tech solution can scale in the right regions without worsening water stress.

Swamp coolers, or evaporative coolers, have moved from an early 20th-century novelty to a durable low-energy cooling option at a moment when electricity grids are straining under rising heat. Reporting published Aug. 18, 2026, by Local10 and News4Jax draws on The Associated Press to trace how ancient cooling principles — fanning air over water in clay pots or jars — were refined in the United States into a mechanical system by Oscar Palmer in 1908 in Arizona. By the 1930s, the devices had changed entire swaths of the country, cooling southwestern states such as New Mexico and Nevada. The mechanics are simple: a fan pulls fresh hot air through vertical porous pads saturated with water; the water evaporates, cooling and humidifying the air before it is directed indoors.

“

Eric Verpolegen, founder of CoolVeg, a nonprofit focused on evaporative cooling for fruits and vegetables, notes that if it is really dry out in Arizona, you get a greater cooling effect.

The distinction between dry and humid air is central to the technology's value. In arid regions, evaporative cooling is highly effective. Eric Verpolegen, founder of CoolVeg, a nonprofit focused on evaporative cooling for fruits and vegetables, notes that if it is really dry out in Arizona, you get a greater cooling effect. But in humid regions, swamp coolers and fans fall short because the air is already saturated and cannot handle more water. This inherent limit is why swamp coolers never fully displaced vapor-compression air conditioning, and it matters more as experts cited in the report say humidity has been worsening in some areas. Traditional air conditioning did not become standard in the U.S. until the 1950s, and even now central air conditioning remains a luxury. Swamp coolers endure as a lower-cost, lower-energy alternative for places where the climate allows.

From a climate and energy perspective, the value proposition is significant. Vapor-compression air conditioning is a major driver of peak electricity demand, especially in the Southwest and other hot, arid regions. Evaporative coolers can reduce electricity use and peak load because they rely on a fan and water pump rather than an energy-intensive compressor. Ankit Kalanki, principal of cooling at RMI, a nonprofit dedicated to clean energy, frames the opportunity succinctly: 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. This makes swamp coolers relevant not only for carbon-conscious cooling but also for cooling access equity, off-grid or under-electrified settings, and low-income households in dry climates.

Yet the technology carries trade-offs. Evaporative coolers use water continuously, which can conflict with drought conditions in the southwestern states where they work best. They also add humidity to indoor air, limiting their use in the increasingly humid conditions that climate change may be bringing to some historically dry regions. The report does not introduce a new product or company, but it resurfaces historical understanding to inform today's adaptation debate. It illustrates how low-tech, passive or semi-passive cooling can complement high-efficiency air conditioners and heat pumps rather than compete with them.