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Air Conditioning
Wed Jul 27, 2005
Listen in RealAudio 
The sounds of July are more than just fireworks. The drone of air conditioning has
become as common as cricket chirps or rumbles of thunder. In the summer, you can
hardly enter a building without being engulfed by a blast of artificially cooled air. Hi, I'm
Bryan Yeaton for The Weather Notebook.
Fifty years ago, air conditioning was a novelty, and, fifty years before that, it didn't even
exist. In the 1800s, engineers tried cooling air by blowing it over ice blocks, but the
resulting air was only slightly cooler and very humid. Inventors couldn't escape a basic
law: you can't cool muggy air without drying it out first.
In 1902, a young engineer named Willis Carrier solved this problem. He ran air
through a cool mist so that some of the water vapor in the air would condense on the
mist droplets, just as moisture collects on a cold glass on a hot, humid day. Later on,
the mist was replaced by metal coils filled with cold pressurized gasses, just like in a
refrigerator.
The first air conditioners were bulky, and through World War II they were used mainly at
large institutions like hospitals, factories, and theaters. The first window units
appeared in 1951, and before long home air conditioning swept the country. Summer
is certainly more bearable with A/C, but some things have been lost. Southern
architects used to design homes with huge windows, high ceilings, and long hallways
to help circulate air. And then there was the veranda, where Southerners spent the
days, as writer Oliver Jensen recalled "sniffing the honeysuckle, consuming gallons of
iced tea and ginger ale, singing, philosophizing, or simply watching the grass
grow."
The Weather Notebook is funded by The National Science Foundation, and
underwritten by SubaruDriven By What's Inside.
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