Q. Which saves more gas: driving with the windows closed and the air-conditioning on, or AC off and windows open?
A. That depends on conditions.
“Today’s cars are designed to be very aerodynamic,” said Glenn Bower, a senior scientist at the Engine Research Center at UW-Madison. “They ‘cut’ through the air at moderate speeds. At lower speed, stopping and starting dominate the vehicle’s energy consumption, while at highway speed (45 to 65 mph), most of the power is lost to the air we drive through.”