Is it really true that using the a/c while driving burns more gas? Or does it vary by car type?

Question

In particular, my car is a BMW 330. definite gas burner??

versus a Toyota Camry??

Answer 1

that is true, the a/c compressor puts a load on the engine. However, you are better off on the highway with a/c than having the windows rolled down, with the windows down it acts almost like a parachute on the car, the a/c uses less energy than the drag. i found great increases in milage by using a/c on the highway, and in city driving rolling down my windows and turning of the a/c, I got almost 2 MPG by doing this.

Answer 2

The question was, does it use more gas, the answer is yes.

The second part was does one car use more as aresult of using a/c than another, the answer is yes.

Does it vary by car type, yes.

Why? the system adds parts so it adds weight.
It makes drag so it makes less horsepower at the flywheel
because its driving the a/c compressor too when the clutch for a/c is engaged.
An important note to keep in mind is, the a/c works also in defrost and bilevel or def and face vent register, of course it does run the compressor on min and max a/c.
The reason is it dries the air to clear the windows fast and remove the humidity for increased realized effectiveness to the passengers.
Check your car to see what settings run the compressor, and you can pick the setting that doesn't when you want more horse power or to save gas.
You can open the fresh air/recirc door and run the blower to push fresh air inside the car when this is the case on many setups.

Answer 3

If you have tachometer (the dial that shows your car's rpm) you can see (if you're sitting idle) that the rpm will go up (just a little, like 200-300 rpm) when you turn the AC on. If your engine has to work more, then more gas is going to be used. This difference will not be noticeable in mpg, but in essence, yes it does burn more gas.

On the other hand, cars are designed to be aerodynamic, and rolling the windows down pulls air into the car and creates drag, disrupting the aerodynamics of your car.

Answer 4

A better question would be, does the car use more gas with all the windows down or with the air conditioning on?

"Mythbusters" did a show on this, and they found very little difference.

Yes, there are probably differences from car to car as well. I think you already know, or can easily find out, the answer to your original question - just step on the gas when the A/C is not on vs. when it is on, and see the difference in acceleration.

Answer 5

Yes, running the AC compressor steals power from your engine to cool you down.

Kind of like driving uphill the whole time it is on. But then experts have shown driving with the windows down creates drag which can be almost as bad.

SO for real fuel economy you keep the windows shut, AC off and figure out a new way to keep cool too.

Answer 6

Studies have shown the aerodynamic drag from the windows down at highway speeds wastes more power than using the A/C. So roll the windows up and enjoy the cool air!

Answer 7

Yes it uses more gas because more gas is needed to provide the power to the AC system

Answer 8

TRUE---TRUE---TRUE!!! The compressor of an air-conditioning unit has to "pump-up" a lot of pressure in order for it to work. That means more drag on the motor AT THE SOURCE which is harder on your gas mileage than almost anything at the tires because of the gear ratio of the drive train.

Answer 9

most of the time you will burn less gas using the AC than driving with the windows down!

Answer 10

Only worry about rolling the windows down if you have an SUV. Otherwise, the difference is marginal, and you're fine. If you have a more fuel-efficient car to begin with, you don't need to sweat it.