Before air conditioning became universal, the only way for drivers to cool off was what some old-timers in Tennessee called 'four and 60.'
That's short for 'all four windows down and 60 mph.' In the early days, it seemed as though driving fast with the windows down was the best cooling system the car industry could come up with.
Suppliers started tinkering with auto air conditioning in earnest around 1930. The results were 'pretty hokey, by our standards,' said Warren Wiese, an engineer who retired in 1991 from air conditioning supplier Delphi Harrison Thermal Systems.
According to Harrison's files, non-starters through the 1930s included liquid nitrogen, a 'vapor jet' system that used a water-alcohol mixture, an 'air cycle' system that used a turbine-powered compressor and a 'gasoline vaporization' system that required 26 gallons of gas an hour.
In the 1930s, according to Americans on Vacation, drivers in Southwestern states could rent a 'hang-on' air conditioner that contained cold water or ice in a cylinder that attached to the car window. It cooled the interior when air blew through it.
Some offices and commercial establishments, especially movie theaters, had early forms of air conditioning that required miles of piping and heavy machinery.
It took almost 10 years from the first industry experiments before Packard Motor Car Co. introduced the first factory-installed air conditioner, on a 1940 model at the 1939 Chicago auto show. It ran on a compressor, but the refrigerating coils were behind the back seat. It would be 30 years after that, in 1969, before the Big*3 installed air conditioning in more than half their new cars.
Part of the problem was that the car companies charged more or less the same amount within the lineup, whether the installation was on an entry-level model or the top of the line. Prices relative to the total cost of the car crept downward as demand spread. Buick charged $430 for air conditioning on the least expensive, full-sized V-8 Buick in 1958, and the same amount seven years later, in 1965. In 1971, at $442, optional air conditioning on a comparable Buick cost 11.7 percent of suggested retail, compared to 14.5 percent in 1965.
In 1977, Cadillac and Lincoln were the only brands with standard air conditioning across the line. Today, air conditioning installations are more than 98 percent.
Back in 1930, all that was a long way off. One experiment at the General Motors Research Laboratories that year used blocks of ice, jury-rigged in the back of Charles 'Boss Ket' Kettering's personal V-12 Cadillac Town Car, to see how much energy it would require to cool a car. Kettering was general manager of GM Research.
With the back seats removed and a hole drilled into the floor for drainage, the engineers would drive for a while, then stop and weigh the ice, to determine how fast the ice was melting. Their conclusion:
'With the ambient temperature at 95 degrees in bright sunshine, with 40 percent relative humidity and the windshield open half an inch (windshields opened in those days), it required heat removal at 12,000 BTUs per hour to maintain an interior temperature of 85 degrees, at 65 mph.'
In 1990, Gerald Elson, who was then general manager of Harrison, gave a presentation to the SAE that included the ice-block experiment and other information on the early days of air conditioning.
The objective was to bring the temperature down by only 10 degrees, he said, because in the early 1930s, it was believed 'if the temperature was cooled much in excess of 10 degrees, it would cause a person to faint from shock' when emerging from the air-conditioned space.
'What will the people in 2040 laugh at us for?' he asked his audience. Elson is now a GM vice president and general manager of the Midsize and Luxury Car Group.
The 'shock' of too much cold air didn't seem to worry Dr. John Gibbons, a New Yorker who invented an 'air-cooling device for autos,' according to The New York Times of Aug. 16, 1936.
'Inventor Says Apparatus Makes Car Interior 14 Degrees Cooler Than It Is Outside,' the headline said.
The description of the 'device' sounds like the basic layout of the Packard system that would be introduced three years later.
It's easy to wonder how seriously the newspaper took the idea, however. Immediately below the air-conditioning article was a story reporting that somebody in Providence Forge, Va., claimed a rooster had started laying eggs.
New Yorkers had to wait until March 17, 1940, for their first air-conditioned taxi, according to The New York Times of that date. The taxi was a Packard.
According to the book Famous First Facts, the capacity of the first Packard system was 'equivalent to 11/2 tons of ice in 24 hours, when the car was driven at 60 mph, or 2 tons at 80 mph.'
But Packard was interested in getting other things off the ground in 1940, besides auto air conditioning. Also in 1940, according to the Times, Packard agreed to produce Rolls-Royce aircraft engines.
Before World War II interrupted, Packard equipped only 1,500 cars with air conditioning from 1939 to 1942, according to Harrison.
A breakthrough came in 1954, when Harrison introduced for Pontiac the first system in which all refrigeration components fit under the hood, ending the practice of stuffing components in the trunk. Chevrolet followed suit in 1955, with a 'pallet-mounted' unit that could be installed all in one piece, precharged with refrigerant.
Wiese, who retired as chief engineer of the Harrison compressor business, said a major breakthrough was the introduction of 'air-mix' systems, around 1967, when he joined what was then GM's Frigidaire Division. In an air-mix system, all the incoming cabin air passes over the evaporator and is cooled and dehydrated. To regulate the temperature, the controls divert some cold air to the heater core, which is always hot. The hot air and the cold air are mixed to the desired temperature.
A key benefit, Wiese said, is that the temperature can be adjusted quickly. Wiese said demand took off.
Air conditioning went from an installation rate of less than 25 percent of new cars in 1965 to more than 70 percent in 1973, according to the AAMA.
Two oil shocks in the 1970s dented the growth rate of air conditioning - since air conditioning compressors run straight off the engine, they rob gas mileage - but it went uphill again in the 1980s. In the 1994 model year, 98.7 percent of U.S.-built cars had air conditioning.
Said Wiese: 'It really began to explode in the mid-'60s. . . . We were in an extremely rapid growth period. The United States has always led in the development of air conditioning for automobiles.' *
Jim Henry is an Automotive News staff reporter.