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11 things you thought were green -- but there's a catch

Turning off your car's A/C

Photo: 3Neus/Flickr

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Turning off your car's A/C

Most automobile air conditioners increase vehicle exhaust emissions and use refrigerants that are harmful to the environment — not to mention it makes your car guzzle gas. Although rolling down the windows is widely considered to be a far cooler eco-alternative, that's only true if you happen to be traveling slower than 45 mph. Faster than that speed and air drag from the windows ruins the fuel savings from turning off the A/C.