Welcome! It looks like you're new here. Be sure to subscribe to my RSS feed so you don't miss a thing! Thanks for visiting!

With the dog days of summer upon us and the price of gas continuing to rise, many people (myself included) are trying to cut back on the use of their air conditioning to save fuel. An article I read over at Slate Magazine talks about this very issue and what the best method of keeping cool is during the hot summer months; rolling down the windows or turning on the A/C?

photo credit: Cycrolu

I think it is common knowledge that using your car’s air conditioning decreases your fuel economy. According to the article:

“Depending on your vehicle’s design, an active AC can cut fuel economy by anywhere from 3 percent to 10 percent in standard summertime temperatures. During a brutal heat wave, though, the power drain can be near 20 percent—the hotter it is outside, the harder the AC needs to work at maintaining your cabin climate.”

Obviously this is not welcome news to those of us trying to save on fuel and not pass out while driving either. However, the drag on your vehicle posed by open windows gets progressively worse as you increase in speed. Eventually, the strain on the engine to continue propelling the car forward with the increased drag outweighs the fuel savings from not running the A/C.

Researchers from The Society of Automotive Engineers studied this issue back in 2004, using both a wind tunnel and test track in Mesa, Ariz. They looked at two different vehicles, an SUV and a full-size sedan, both of which featured powerful eight-cylinder engines. Their findings were as follows:

“The engineers found that rolling down the windows on the SUV had only a small negative effect, in part because the vehicle’s big, boxy shape was already creating a lot of drag. So, from a fuel-economy standpoint, a driver of an SUV will always do better to shut off the air-conditioner. The sedan, on the other hand, has a sleeker shape and a lower drag coefficient. As a result, its fuel economy was noticeably affected when the windows were rolled down at highway speeds; at around 68 miles per hour (the test’s maximum), there was barely any difference between air conditioning and nature’s cooling. If you were driving the sedan any faster than that, the increased drag would presumably make AC the more efficient option.”

The consensus then is that a good rule of thumb is to drive with the windows rolled down in the city and as you hit highway speeds it’s probably more efficient to use the A/C (not to mention a quieter ride). To read the rest of the article in it’s entirety you can do so here.

As always if you enjoyed this post feel free to Stumble It! or share it with your friends however you choose to do so. Remember to also subscribe to the RSS Feed to stay current with all the news around here as well.

Popularity: 15% [?]