Better fuel economy with windows cracked, or A/C?

[dann_04]

I have heard that windows up a/c on on the highway over 45mph is more efficient than windows down, but the only tests i've seen(mythbusters) is with the windows all of the way down. Typically i will ride with the windows down 1-2 inches on the highway(my car only has two windows, 2003 civic si hatch) so is 1-2 inches down better than up with the a/c on? Is 1-2 inches down better than widows up and blower blasting with no a/c? Or is a/c set to recirculate with blower set relatively low better? I appreciate any help.

[NeilBlanchard]

Hi y'all,

All I know is that if I run my A/C, the fuel economy plummets. And with the windows open all the way, the noise level is pretty high; and noise is a good indicator of drag. Cracked windows, with a little vent fan if needed, is best.

[petty]

he's right, cracked windows, with a little vent fan if needed, is best. Take note that one of the best ways to optimize mileage is to keep up with vehicle maintenance. And don’t waste gas by accelerating up to red lights and stop signs.Don’t let your car idle excessively. Drive as if you have no brakes.

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Autopartswarehouse Car Solutions.

[ankit]

A friend of mine was sitting in my car today and told me that he heard that it is more fuel efficient to use diagonal windows. So the driver's side front and passenger side rear because it somehow causes less drag. I've never heard of that working but wondering if anyone has any experience with it.


I also just crack windows at highway speeds just because I can really feel the drain on the engine the a/c causes even at a low blower speeds.

Edit: another thing that has helped me a lot is a window shade. It was like a couple of bucks at big lots bit it really keeps the car cool. Sometimes it feels like when i return to it after a couple of hours of it being parked in the sun, it seems like it is cooler in the car (normally like an oven). Because of this you don't have to run the A/C immediately or the blower or sweat (your choice) as much because the car wasn't all that hot to begin with.

This is what i'm talking about because i don't know what it is calle.d