Quote:
Originally Posted by TKCamry
I don't have any numbers, but it will depend on the speed. At highway speeds(65 MPH and up), the drag of an opened sunroof(based on my instant MPG dial) uses up more gas than the air conditioning. But at lower speeds(around 40 MPH and lower) the sunroof and the AC break even. |
I'm not so sure it's this simple. The A/C uses an electric motor that will deplete your battery quicker and therefore make your engine run more often. The sunroof would add some drag, but I can't imagine it's that significant and most speeds. A better test would be to drive for a week with the sun roof open, then the next week use A/C. Assuming your driving habits and weather were similar, you would have a better test than the instantanous reading. Just my opinion