Auto Air Conditioning & Heater Repair: Fuel efficiency, car air condition, wind resistance

Question
Hi, two questions: 1. does turning on car air condition use more gas than opening the window while driving? Is it significant? 2. Is higher octane gas more efficient than lower octane gas? Thanks for your advice!

Answer
Hey Lena,

I believe that running the air conditioning wastes more fuel than driving with the windows down. The reason is there is an extra load on the engine to drive the compressor. But thats not to say that when the windows are open that its more fuel efficient, this put wind resistance on the vehicle especially at higher speeds. Higher octane will not give you better gas mileage and you only should use it if your vehicle requires it. I hope that answers your questions.