Myth: Car air conditioning wastes energy.
Reality: Don't sweat it.
Want to save gas and stay cool in the summer? Shut off the AC and roll down the windows. Right? That may save energy in city traffic. According to Consumer Reports, running the AC will decrease performance by two to four miles per gallon.
But what effect will air resistance have at highway speeds? Consumer Reports tested a Toyota Camry at 65 mph and found that AC use burned only slightly more energy than with windows open. Its advice: "Do what makes you comfortable." -- E.F.
NEXT: Wheels: How green are hybrids?