MPG: better w/AC on or w/AC off & windows open?

[prettybluewoody]

Okay, it's summer, we all wanna turn on the AC but we ALSO wanna get great gas mileage. So which way will get the better mileage, the windows closed/AC on or windows open/AC off? Figuring that open windows create drag which reduces the MPG, but the AC certainly uses engine power (read: gas!), my assumption would be that at slower speeds the open windows option would make more efficient mileage, but at higher speeds it'd be the other way around.

So: at, say, 30mph, 40mph, 50mph, 60mph and 70mph, does anybody have anything better than my simple slower w/open windows vs. higher speeds w/AC guesswork?

[CREWZIN]

Myth Busters already did it....

Annotated Mythbusters: Episode 22: Boom Lift Catapult, A/C vs. Open Windows

[TommyNiagara]

Originally Posted by CREWZIN

Myth Busters already did it....

Annotated Mythbusters: Episode 22: Boom Lift Catapult, A/C vs. Open Windows

Yup, seen this one. The did one experiment about pick up trucks as well: open box tail gate up, tonneau cover, or open box tail gate down.

[Roadcuda]

Anytime I've run with my a/c I've seen little if any difference in the mpg I get. But, from what I've seen here on the wide range in mpg that people get that may be a hard question to get a good answer for. I think it all depends on how you drive your car to begin with. I try to drive with a light foot, so I get decent mileage. If you have a heavy foot you may not do as well. I think the only way you'll know for sure is to experiment with it on, or off, and see what happens.

[ucantcme]

I drive with my windows down when it's nice out. The joy of having the wind blow at your face is sweet. Beats A/C anyday.

[CREWZIN]

Originally Posted by ucantcme

I drive with my windows down when it's nice out. The joy of having the wind blow at your face is sweet. Beats A/C anyday.

That works up north Ron, but it's above 90 degrees here all week already this year and even at night it's warm and humid. Early morning is the only time for an open window without the AC.

[ucantcme]

I've lived in New Orleans and in Guam for a total of 5yrs of my life - I know the hot and humid scenario. But still, i enjoyed the windows in the ajar position!

[TommyNiagara]

Originally Posted by ucantcme

I drive with my windows down when it's nice out. The joy of having the wind blow at your face is sweet. Beats A/C anyday.

I agree. The only time I use the A/C is to defog the windows.

[ucantcme]

Originally Posted by TommyNiagara

I agree. The only time I use the A/C is to defog the windows.

x2!!!!

[prettybluewoody]

Not me: if it wasn't for AC, I'd melt! I'd rather do without a heater in the car in winter than no AC in summer.