Gas Savings: A/C vs. Windows - Which is More Efficient?

The debate over the best way to cool a car and save money on gas has many possible resolutions. The answer to which is best depends on the aerodynamics and fuel efficiency of the vehicle.

For Aerodynamic Vehicles

If you drive a sports car that is very aerodynamic, you will save the most on gas money by playing to this car's strengths. Keep the windows up to allow the car the best chance to fight the winds. Since the car is small, it costs little to run the A/C and keep it cool. Help save more gas by keeping sunroofs closed and using sunshades where possible.

For High-Cost Vehicles

If you drive a larger SUV, your car is already fairly bulky when traveling down the highway. It also costs more to cool this car through the A/C. As a result, it is best to keep the windows open for cooling. The main exception would be a very new car or a car with hybrid technology. In this case, look in your owner's manual to see if the car's A/C runs off gas or electricity. It is possible the cooling system is electric, in which case running the A/C is better.