The bringing of air in enclosed spaces to a desired state of purity, temperature, and humidity by mechanical means. Early systems pioneered in the USA included the use of ice (Carnegie Hall, NYC, in the 1890s) and ammonia (New York Stock Exchange, 1904). In 1902–6 Willis Haviland Carrier (1876–1950) of Buffalo, NY, devised the ‘dew-point control’, by which air was washed and saturated, then the temperature of such saturation was controlled automatically, thus determining the moisture-content of the air. The first building to be fully air-conditioned was the Milam office-block, San Antonio, TX (1928), closely followed by the Philadelphia Saving Fund Society offices (1929–32), by Howe & Lescaze.
C. Elliott (1992);Ingels (1952)