History of Cooling and Air Conditioning
Air conditioning, a cornerstone of modern comfort, has a surprisingly rich and inventive history. From ancient methods of passive cooling to today’s high-tech climate control systems, the journey of air conditioning reflects human ingenuity in managing indoor environments.
First Cooling Techniques
(Pre 20th Century)
Benjamin Franklin's research paved the way for air conditioning
Long before mechanical systems existed, civilizations found creative ways to cool their dwellings. In ancient Egypt, reeds were hung in windows and moistened with water, providing rudimentary evaporative cooling. Persian wind towers (badgirs) channeled breezes through buildings and over underground water channels to cool the air. Roman aqueducts and wall-based water circulation helped cool elite homes and public baths.
The scientific foundation for modern air conditioning was laid during the 18th and 19th centuries. In 1758, Benjamin Franklin and British chemist John Hadley conducted experiments with evaporation, discovering that the rapid evaporation of volatile liquids like alcohol could drastically reduce temperature. They noted that liquids with high evaporation rates could cool objects below the freezing point of water—even in warm rooms. This experiment was among the earliest scientific recognitions of how phase change could be used for cooling.
In the 1840s, Dr. John Gorrie, a physician in Apalachicola, Florida, believed cooling was essential to treating illnesses like yellow fever. He designed a device to create ice using compressed air, intending to lower room temperatures in hospitals. In 1851, he received the first U.S. patent for mechanical refrigeration. Unfortunately, Gorrie’s vision was thwarted by lack of funding and opposition from the ice industry, and he died without seeing his idea come to fruition.
The Start of Modern Air Conditioning
(Early 20th Century)
The modern air conditioner was born in 1902, when Willis Carrier, a young engineer, designed a system to control humidity and temperature at the Sackett-Wilhelms printing plant in Brooklyn, New York. Carrier’s solution was to blow air over chilled coils, which not only cooled the air but also dehumidified it by condensing moisture. This dual effect—temperature and humidity control—formed the basis of modern air conditioning. He called it the Apparatus for Treating Air, and in 1906, he received a patent for his invention.
One of the first centrifugal refrigeration compressors developed by Willis Carrier
Carrier's invention marked the beginning of true climate control—not just cooling, but regulating temperature and humidity together. In 1915, he founded the Carrier Engineering Corporation, which would go on to dominate the HVAC industry.
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Initially, air conditioning was limited to industrial applications—textile mills, printing plants, and pharmaceutical labs. But by the 1920s, public spaces began adopting the technology. In 1925, the Rivoli Theater in New York City became one of the first to install a Carrier system, drawing crowds eager to escape the summer heat.
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By the 1930s, upscale department stores and office buildings followed suit. At the 1939 World's Fair, the Frigidaire “Igloo of Tomorrow” exhibit introduced home air conditioning as a futuristic luxury.
Residential Growth and Environmental Concerns (Latter half of 20th Century)
Modern Air Conditioning
After World War II, advances in refrigeration and manufacturing made air conditioning more affordable. Compact window units began appearing in homes in the late 1940s and 1950s. By the 1970s, central air systems became more common in suburban homes, especially in the growing Sunbelt states of the U.S., where AC was vital for year-round comfort.
Air conditioning also transformed American architecture—leading to sealed buildings, glass skyscrapers, and sprawling, climate-controlled shopping malls.
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However, by the late 20th century, concerns about ozone depletion led to major changes in refrigerants. Older systems used CFCs (chlorofluorocarbons), which were phased out starting in the 1980s under the Montreal Protocol. New refrigerants like R-134a and later R-410A became the standard.
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Modern systems now emphasize energy efficiency, smart thermostats, and eco-friendly refrigerants (such as R-32 and R-454B). Innovations like variable-speed compressors, geothermal systems, and ductless mini-splits have made cooling more precise and sustainable.