(CNBC) — Want to save fuel on those long summer highway drives? Don’t open the window. Crank up the air conditioning. ( Tweet This)

That’s just one of the useful — and frequently surprising — tips available from fueleconomy.gov , the go-to web site for information on fuel economy.

While running the AC does increase fuel consumption, it’s more efficient than driving with the windows open at highway speeds. The open windows increase the car’s aerodynamic drag, and that makes the engine work harder, according to the Environmental Protection Agency.

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