As Memorial Day began, so did the first over-eighty-degree, sunny, humid day of my summer. As I was driving home from the Memorial Day festivities (in my car that had sat in the sun for hours) a debate began in my head on which was more fuel efficient: having the windows down or having the air-conditioning on? This question has plagued me since I began driving and with gas approaching $4 a gallon, I wanted a final answer!
When I got home, I read through many articles and finally came up with an answer (sort-of): it depends. The method of cooling that is best for the environment and your car’s fuel efficiency depends on the speed you are traveling at. For stop-and-go city/town traffic, it is more fuel efficient to drive with the windows down. But, as speed increases to around 45-55 mph fuel efficiency is maximized by having the air-conditioning on. This is due to the large amount of wind drag that occurs from having windows open at high speeds.
So, I guess the real answer is to use your own judgment. Most websites tossed around a 10-20% gain of fuel efficiency when drivers made the correct cooling choice based on their speed. Good luck, and I wish you all happy, safe and cool summer driving!
Filed under: improving gas mileage
