On this day in 1939, the 40th National Automobile Show opened in Chicago, Illinois, with a cutting-edge development in automotive comfort on display: air-conditioning. A Packard prototype featured the expensive device, allowing the vehicle's occupants to travel in the comfort of a controlled environment even on the most hot and humid summer day.
After the driver chose a desired temperature, the Packard air-conditioning system would cool or heat the air in the car to the designated level, and then dehumidify, filter, and circulate the cooled air to create a comfortable environment. The main air-conditioning unit was located behind the rear seat of the Packard, where a special air duct accommodated two compartments, one for the refrigerating coils and one for the heating coils.
The capacity of the air-conditioning unit was equivalent to 1.5 tons of ice in 24 hours when the car was driven at highway driving speeds. The innovation received widespread acclaim at the auto show, but the expensive accessory would not be within the reach of the average American for several decades. However, when automobile air-conditioning finally became affordable, it rapidly became a luxury that U.S. car owners could not live without.