On 7 October 1935, Ralph Peo of Houde Engineering, Buffalo, New York, applied for a patent for an "Air Cooling Unit for Automobiles". U.S. Patent 2,099,227, was granted on 16 November 1937. In 1939, Packard became the first automobile manufacturer to offer an optional air conditioning unit in its 1940 model year cars.

The first car to offer a factory-installed air conditioning system was the 1940 Packard, which was introduced at the 40th National Automobile Show in Chicago in November 1939. This early system, manufactured by Bishop and Babcock (B&B), was a massive, expensive option that occupied much of the trunk space and lacked a modern dashboard switch; to turn it off, the driver had to physically stop the car and remove a belt from the compressor under the hood. While a New York firm had offered aftermarket "car cooling" as early as 1933, Packard was the pioneer of the mass-market integrated unit. It wasn't until the 1954 Nash Ambassador that the industry saw the first fully integrated, compact, and affordable front-end system (the "All-Weather Eye") with dash-mounted controls. This 1954 innovation set the standard for the modern climate control systems that we take for granted in almost every vehicle on the road in 2026.