Have you ever heard, "it's better to roll up the windows and run your air conditioning than drive with the windows rolled down"? The idea is, your car is aerodynamic. Open windows make the car less aerodynamic, so you get lower gas mileage.

Of course, running the AC drains power and reduces mpg as well. So which is really better?

It turns out-- neither. Maybe. Sort of?

Alright, so the Mythbusters team called this one "Myth Busted." They found that a car with its windows rolled down ran 15% longer than a car with the AC on before running out of fuel.

However, their computer simulation showed the opposite effect, and you have to consider the fact that if one of the drivers had more of a lead foot, or wobblier steering, it could have affected the results.

Another compounding factor is speed. The higher the speed, the greater the effects of wind resistance. So during this 45mph test, it may have been true that rolling windows down is better, at highway speeds the result may have reversed.

Our recommendation? Cool off however you want, and come visit John Johnson Select Used Cars to test drive a vehicle from our used inventory.

Categories: Video