Air conditioning
Modern air conditioning emerged from advances in chemistry during the 19th century, and the first large-scale electrical air conditioning was invented and used in 1902 by US inventor Willis Carrier. The introduction of residential air conditioning in the 1920s helped enable the great migration to the Sun Belt in the United States.
Willis Carrier
In Buffalo, New York, on July 17, 1902, in response to an air quality problem experienced at the Sackett-Wilhelms Lithographing & Publishing Company of Brooklyn, Willis Carrier submitted drawings for what became recognized as the world's first modern air conditioning system. The 1902 installation marked the birth of air conditioning because of the addition of humidity control, which led to the recognition by authorities in the field that A/C must perform four basic functions:After several more years of refinement and field testing, on January 2, 1906, Carrier was granted for an "Apparatus for Treating Air," the world's first spray-type air conditioning equipment. It was designed to humidify or dehumidify air, heating water for the first function and cooling it for the second.