Tuesday is recognized as the birthday of air conditioning -- be thankful this year, because you'll need it.
Willis Carrier, an engineer in Buffalo, N.Y., is credited with planning a device to regulate heat and humidity in a Brooklyn printing plant. He drafted the plans for the device July 17, 1902.
Carrier patented the invention four years later, and in 1915, he and six colleagues formed the Carrier Engineering Corp. The device contained a spray nozzle originally designed for insecticide and it controlled both temperature and humidity.
Of course, cooling systems have become more sophisticated since then. Aside from making us more comfortable, it has also saved lives -- heat has contributed to the deaths of 18 people in Maryland so far, in some cases potentially because they lacked electricity.
Air conditioners in the Baltimore area have been working extra hard so far this year. Cooling degree days, a measure of how much cooling is needed to keep homes at 65 degrees, are well ahead of normal and slightly ahead of where they were a year ago at this time. (If a day's average temperature is 85 degrees, for example, that adds 20 degree days to the tally.)
In an average year, Baltimore will have accumulated 499 cooling degree days through July 16; so far this year, the tally is 736, ahead of 729 at this time last year.
So, how low do you set your air-conditioning thermostat?
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