What is the effect on fuel mileage of using air conditioner versus not using?

Question

What is the effect on fuel mileage of using air conditioner versus not using?

Answer 1

very little ..... really you burn more with the windows down

Answer 2

On the highway , not much difference. In the City, it will be more noticable. The aero effect with the windows down and the air entering the vehicle on the highway @ 60 mph are close to the same mpg as with the aircondition on.    good luck!!  Stay comfortable, it's only money !

Answer 3

better mileage at highway speeds with windows up and ac on.

better at low speeds with windows down ac off