Reply #25: That sounds kind of hard to believe.

[EOTE]

Anything that runs off of your accessory belt robs horsepower and therefore driving at equivalent speeds would require more fuel. I've even noticed a decrease in fuel economy in my car since I installed a lot of aftermarket amps in my car. The reason for it is that because my battery is draining quicker, my alternator needs to run more which puts more strain on the accessory belt which requires more fuel. It requires a lot of energy to run an A/C compressor, I find it hard to believe that that energy is free.