I know mythbusters did a show on this but I didn't see the results. Anyone who can answer me with websites/ data to back up their claims would be a great help. Thanks!
2007-07-06 04:44:37 · 7 answers · asked by Anonymous in Cars & Transportation ➔ Other - Cars & Transportation
On mythbusters, they showed that it depends on the speed of the vehicle. From their graphical calculation, they determined that a speed of about 45mph was the break point.
Driving less than 45 mph, windows down was more efficient.
Diving more than 45 mph, windows up and A/C on was more efficient.
However, the most efficient obviously is with windows UP and A/C OFF!
If you understand Forces, you'll know that drag forces are directly proportional to the square of the velocity. Which in laymans terms says that that faster your going, the drag forces will dramatically increase.
ie, if you're going 10 mph the drag force is proportional to 10*10 = 100, if your going 30mph the drag force is proportional to 30 * 30 = 900. So by going only 20 mph faster, you've almost increased the drag forces by 8x.
2007-07-06 04:58:21 · answer #1 · answered by hsueh010 7 · 0⤊ 0⤋
It also depends on the car. Think of it this way...running the AC compressor on a hot day puts a fixed load on an engine and that cuts into the fuel mileage. That load is more influential on a small, low horsepower engine than it would be on a bigger, more powerful car. My commuter is a Honda Insight. I'm currently getting 72MPG at normal freeway speeds. If I turn on the AC, I can really feel the drag and I will dip into the 50MPG range to keep the 70MPH speed of surrounding traffic. On my 2001 Pathfinder, I can't tell if the AC is on...in power or fuel mileage. How smoothly you transition from stop to go...how you time red lights, how close you follow other traffic...all have way more influence than the AC on fuel mileage in the Pathfinder. In the Insight, you push the AC button on the dash and the fuel mileage meter plummets to 50MPG.
2007-07-06 05:15:06 · answer #2 · answered by Ron C 1 · 0⤊ 0⤋
I, too, consider Michael M. i'm a driving force for a residing, and have pushed 4 million miles + over the line, and have chanced on on a number of activities that living house windows down= extreme wind drag. in spite of the undeniable fact that, the tinted plastic windbreaker fairings which you will stick to the door jambs easily DO make a distinction, besides as enable rolling the window down a splash in any climate. they have revolutionized a/c structures lots interior the final 10-15 years that it makes a negligible distinction on gas economy besides.......
2016-10-20 01:28:59 · answer #3 · answered by Anonymous · 0⤊ 0⤋
I think the A/C was marignally better in their tests. It just depended on how you were driving. On the highway, the A/C was better because the drag from the windows being down negated the fuel savings from not running the A/C. In stop an go city driving though., I think it's about the same.
2007-07-06 04:48:26 · answer #4 · answered by Anonymous · 0⤊ 0⤋
According to a study done about 10 years ago, There is no real advantage either way. Excluding the normal wear-and-tear on your AC system. Which is normally minimal.
2007-07-06 04:57:57 · answer #5 · answered by AL W 2 · 0⤊ 0⤋
i would have to say with the AC on. the windows down add resistance depending on how fast you drive.
2007-07-06 04:48:52 · answer #6 · answered by nik n 2 · 0⤊ 0⤋
Windows down.
Definitely.
2007-07-06 04:49:20 · answer #7 · answered by Joe M 5 · 0⤊ 0⤋