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Air Conditioning
Fri Jul 04, 2003
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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