Does AC Burn Gas More Than Open Windows? Find Your Answers!

Does Car Air Conditioning use gasoline? Of course, it does! So, it’s a no-brainer that switching the air conditioning system on in your car will hurt the gas mileage, just like any other feature that draws power by burning fuel. The question is does AC burn gas more than keeping the windows down?

How Much Gas Does AC Use?

Running a car’s AC system burns fuel but the amount of the consumption depends on the AC compressor operation. It could be up to 5% decrease in gas mileage if you run the air conditioning on a scorching summer day with the car full of passengers.

For example, if you are driving a VW Jetta diesel car with a 90HP engine that gets rid of approximately 9HP from the drivetrain when engaged, it will consume about ½ liter extra fuel after 100km of driving.

does ac use gas
AC’s fuel consumption depends on several factors. Cre: bizoo_n – Fotolia

However, the thing consumes the most amount of fuel is keeping the engine and air conditioning on when the car is idling. Such idling affects even the mileage of the Toyota Innova too that is hardly affected by the running air conditioner.

Does AC Burn Gas More Than Windows Down?

It actually depends on your car’s make and model, driving habits, the speed of the car, and a few other factors. The running of AC does burn gas but the open windows enhance the vehicle’s aerodynamic drag, making the engine to work harder and burn more fuel.

The Society of Automotive Engineers in test an SUV and a full-size sedan in two different tracks in 2004. According to the test, driving at 50 or 55mph with windows open was worse for the mileage. At that speed, the fuel efficiency drops by 20% with windows down while the rate is 10% with the air conditioning on.

However, another test done by the Consumer Reports in 2012 showed a slightly different result. The fuel efficiency of a Honda Accord dropped by around 3mpg when the car ran at a 65mph speed with the AC on. So, it seems that the mileage efficiency depends on the environment, the car’s speed, car’s model, and a few more conditions. There is no one condition that can fit all the cars and drivers.

          SEE MORE

When Does AC Burn Gas More Than Open Windows?

The AC proves to be burning more fuel than open windows when you are driving at less than 50 miles per hour. So, the best practice is to keep the windows down when the weather is a bit cooler and you are driving inside the city. The drag will be ignorable at that speed, so the engine won’t consume much fuel.

does ac burn gas
Driving with open windows create aerodynamic drag. Source: HotCars

>> Buy a high-quality used car at best deal from Japanese authorized dealers here <<

Check out the video below to see more details:

The AC suits better to a highway drive in hot weather. However, if you find that the air conditioning is draining the fuel rather quickly or overheating the engine, turn it off. It mainly happens when the level of fuel in the oil tank is dangerously low.

Remember that you should not try to save the small amount of fuel by turning the AC off in a sweltering hot day. The excessive heat could cause health problems or make it bothersome to concentrate on driving.