To A/C or Not A/CThere's no question
air-conditioning makes extra work for the engine, increasing fuel use.
But car air conditioners are much more efficient today than they used
to be. In around-town driving, using the A/C will drop fuel economy by
about a mile a gallon.
Meanwhile,
driving at higher speeds with the windows down greatly increases
aerodynamic drag. As speed increases, drag becomes more of an issue,
making A/C use the more efficient choice at high speeds.
At most
speeds and in most vehicles, A/C use drains slightly more fuel than
driving with the windows down, contends David Champion, head of auto
testing for Consumer Reports. "My final take on is that it's very
close," says Phil Reed, consumer advice editor for Edmunds.com. "It's
hard to measure the difference and every vehicle is different."
The
best choice - if temperature and humidity allow - is to keep the
windows rolled up and to turn the A/C compressor off. You can keep the
fans running to blow in air from the outside, but your car will be as
aerodynamic as possible while still letting you breathe. You will save
gas, but the fuel economy improvement will be slight.
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screw it, i'm turning my a/c on. 1mile/gal isn't much at all.
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