Fuel Economy While Using Air Conditioning on 2007 Pontiac G5

I drive a 2007 Pontiac G5 that has a pretty decent Air Conditioner, however, I tend to only use it either when the weather tempature reaches above 90 degrees or I have passengers in the car with me. The reason I hesitate to use the Air Conditioner is that I tend to believe that its use drasticly reduces the fuel economy of the engine and therefore, wastes gas. My friends and family on the other hand believe that the Air conditioners in cars today are much more effecent than those in previous cars and that the drop in fuel economy is very small and therfore, the comfort of the air conditioning is worth lossing a little fuel economy.

Please help settle the argument once and for all. Thanks.

2 answers
Well your friends and family and yourself are all right. While using the A/C does reduce fuel mileage, it's not nearly as bad as it was at one time and it's also true the systems are more efficient. Where I live in the southeast, I'm willing to pay for the comfort. Fuel mileage has been increased more from a decrease in the overall weight and components of the car than anything, along with smaller more fuel efficient engines and aerodynamics. Bottom line is both of you are correct! Why don't you run a test for yourself. Run a tank of fuel using the A/C and then a tank without it under comparable driving conditions. I find that customer driving habits are far more responsible for good or bad fuel mileage.
The cause for the loss of fuel economy is because it puts a load onto the engine. The AC compressor in your car that gives you AC is ran by a belt that is powered by the engine. Turning on the AC turns on the compressor, which in turn demands power to run it. It then can take more effort for the engine to run the engine. On older cars, yes it was really bad for the engine