Driving with the windows closed and the air conditioning off, and using the blower fan to keep you cool, or; Driving with the windows open. When the A/C is switched on, the car uses engine power to drive the A/C compressor; this is absolutely going to use more gas than situation 1. read more
The SAE found that running an air conditioner in an automobile decreased gas mileage by 5 to 10%. Stanford University and SAE both recommend driving with your car’s windows down if you are traveling on city streets. read more