With the winter ending and spring beginning, it’s time to start looking at the air conditioning in your car. A major topic related to air conditioning is its effect on gas mileage. It is important to way the benefits and downsides to air conditioning. It is true that air conditioning does affect the gas mileage of your car, but probably not as much as you’ve been led to believe. Many people believe that driving with the windows up and the air conditioning on will use up much more gas than driving with the windows down and no air conditioning.
As with most questions in the world today, scientists have finally decided to answer this. In a study conducted by the Society of Automotive Engineers, it was determined that driving with the windows up and the air conditioning on is much more fuel efficient than alternatives. Driving with the windows down can reduce fuel efficiency by as much as 20 percent. Now you’re probably wondering, why is driving with the windows down so bad for my gas mileage? It is due to the drag increase on the car, especially at high speeds. Cars are designed to be as aerodynamic as possible, with air washing over the car. When the windows are rolled down, the air cannot wash over the car.
Instead, it enters the windows, exerting a force on the car. The force exerted is proportional to the square of the velocity. This means that when you double your speed, according to automobile brands you actually quadruple the drag force on your car! Obviously this drag force is much lower when driving around town, so on a nice spring day don’t be afraid to roll the windows down. Just remember, when you drive on the highway it’s best to roll the windows up and use the air conditioning.