Does running the A/C in the car use more gas than opening the window?

Question

Does running the A/C in the car use more gas than opening the window?

Answer 1

YES

Answer 2

Depends on the speed.  For most passenger cars, at speeds above 60 mph, opening the windows uses more gas than the AC because of the drag force.  At low speeds, there is almost no drag force so opening the windows doesn't use much gas, and it becomes better than the AC.

Answer 3

It depends on which window(s) that you open and by how much, and also how fast you are going.

Air conditioning takes power to run, so your engine has to work a bit harder in order to supply that power, so it uses some additional gas.

On the other hand, if you open windows, that will will cause additional air resistance from the air swirling  about and through the, the faster you go, the more air resistance.

On my old Acura Legend, when I turned off the air conditioning and just had the sun roof cracked, I picked up an extra couple of miles per gallon at 60 mph, other cars may differ.

Answer 4

yes, it takes a lot of energy from the engine so the engine has to work more which means it has to use more gas.

Answer 5

duh just test it ones, drive a whole tank of gas without using a/c and then do it with only ac

Answer 6

no brainer. yes...more load you ask of a motor, the more fuel it uses

Answer 7

At low speeds,   yes.   Higher speeds,   depends on the vehicle.

At low speeds,   aerodynamics does not play such a roll in fuel mileage,  that happens after reaching 55-60 mph for most vehicles.   Leaving the A/C off and rolling the windows down will conserve fuel,  and if just getting into the vehicle will let the heat out quicker than trying to overpower it with A/C.    Once you get to where you can cruise steady at higher speeds,   less fuel needed to start and build speed,   running the A/C should not impact mileage so badly.

Answer 8

Well you can tell when its time to roll up the windows and use A/C. When there is strong wind usually around 50mph then its more efficient to use a/c. If you have a curved back window and a 4 door car then open the driverside and right rear window for good circulation.

Answer 9

This is a great question, and has some very interesting science involved. In one of their earlier episodes (a classic one, at that) the Mythbusters showed that windows opened uses less gas - BUT, as would be confirmed by testing, it was later determined that there was a split in fuel efficiency around 50 mph (A/C becoming more efficient at that point), depending on the model of the car. So it just depends on whether you're on the highway, or on a suburban road. If you don't want to have to keep switching around all the time, just pick the one that works the best for you.

Answer 10

it dosent on the road because the engine is moving arounr 2-3000 rpm's anyway. at stand still it will use more gas because the compressor has to run