The great debate, A/C On vs. Windows Down while driving…

June 22, 2006

Thanks to my sweet wife for forwarding this Bankrate article to me about fuel efficiency while driving in the heat. I’ve been struggling with this question for some time now (since it’s been in the 90s here in Rockville, MD for a few weeks) and agree with the article that there are 2 ways to look at this issue: highway driving vs. city driving. So, which kind of driver are you?

If you’re driving in the city, you’ll get your best fuel savings by driving with the windows open rather than using the A/C. However, depending on your city, this may not be the safest way. Use your best judgement while driving with your windows down. It only takes a few seconds for a leisurely drive or rushed commute to turn into a car-jacking.

Now that I got you all panicked, let’s get back to fuel-efficiency. So, A/C off & windows down while city driving is more fuel efficient than A/C on, but what about highway driving? Well, the opposite holds true. Once you hit a certain speed (generally 55-60mph) for sustained periods, the wind will drag your vehicle down if your windows are open, costing you 20% or more in fuel consumption. For best fuel efficiency, turn on the A/C (to a low fan setting) and roll the windows up.

Overall, your best bet is to drive with the windows up and the A/C off, like my wife, who doesn’t seem to produce her own body heat and appreciates the sun’s help 🙂

Next up…Which is more efficient: Tailgate Up or Down (pickup trucks only)?