how do using a/c and open windows affect auto mileage?

Answer 1

these increase fuel consumption for 2 reasons .using a/c increases fuel consumption due to power being used to power the a/c's compressor. this is a pump to circulate refrigerant gas around the system. open windows increase fuel consumption due to increased wind ressitance /drag of the car when windows are open.

Answer 2

A/C kills mileage a lot while windows really do not. Open windows can create a free stream over them if the car's body is designed the right way and cause less drag. Its actually more efficient to drive with a pickup tailgate up because of the air pocket that is formed in the back that allows air to flow over instead of crashing down into the bed. The AC steals a lot of engine power so you have to give it more gas to keep the same speed.

Answer 3

As others said, open windows create drag, which most of the power used in a car is used to overcome, so it dramatically decreases gas mileage. Although using the air conditioner uses power from the engine, you will get better gas mileage if you run the air conditioner with the windows up, than if you turn the AC off and roll down the windows. Of course, nothing can beat that feeling of wind in your hair, so I do it anyway!

Answer 4

Open windows causes drag on the vehicle, requiring more gas to maintain the same speed as the same vehicle with all windows closed.

AC on means that two or maybe just one pump runs off the electricity from the alternator. So, the alternator needs more engine power to maintain the same electrical output as compared to the same vehicle without its AC on. The electrical output comes from the turning of the rotor, and thus this uses more gas.

Answer 5

The a/c draws power from the engine which causes the engine to work harder, thus burning more fuel. However, having the windows down creates drag, forcing the engine to work harder to maintain speed.