4/60 air vs. AC on for better gas mileage?

[Go Mifuni]

Ok, here we go. I'm trying to end a debate with the wifey over this. :help:

Which do you think would provide the best gas mileage at highway speeds:
Driving with the AC off and the windows down (increased drag, more HP?)
or
Driving with the AC on and the windows up (less drag, less HP?)

I believe it's with the windows up and the AC on. My reasoning is, besides the obvious decrease in drag, the AC compressor pully is turning anyway even if it's off.

:twocents: please?

[sd8683]

I remember they did a comparison on mythbusters but for the life of me I can't remember what the outcome was??

Sorry mike

[Vortex]

A/C on, windows up is much more efficient.

[Dr Caleb]

http://en.wikipedia.org/wiki/MythBusters_(season_2)#AC_vs._ Windows_Down

Windows open is more efficient, up to 50MPH. Over that (55+), A/C becomes more efficient.

[Mike Poore]

If my windows are down, just a crack, Barbara starts howling about her f'n hair.

Now, add up the accumulated years of complaining and the cost in doctor bills and life shortening crap you have to put up with over such stupid nonsense, and you quickly realize that keeping the windows UP, is by far the most cost effective choice.

Remember, you need to consider the cost of the bottles of Tums in this equation. ;)

[Bigdogjim]

NOTHING! Windows up is a tad better...............

[Bluerauder]

http://en.wikipedia.org/wiki/MythBusters_(season_2)#AC_vs._ Windows_Down

Windows open is more efficient, up to 50MPH. Over that (55+), A/C becomes more efficient.
I don't think that this can be said with any certainty. Their test used only two point estimates ... one at 45 mph and one at 55 mph. They calculated fuel consumption differently .... one by an air flow estimate and another by actual consumption. The test results would vary by specific car, model, aerodynamics, 2 vs 4 windows, window area, engine size, AC setting, outside ambient temperature, and a whole lot more variables.

The best that you can say without a bunch more statistically valid testing iterations using the same method of fuel consumption is that the "windows down/AC off" condition is generally better at low speeds than the "windows up/AC on" condition at higher speeds. My personal opinion is that the breakpoint is in the 30-35 MPH area (above which you start to notice the turbulence and below which it isn't really noticeable). Again, the specific point would depend on the particular car and other things ^^^^ above.

That said ..... I agree with Mike. Windows up reduces all the other collateral costs of life. ;)

[Vortech347]

In the MM I keep them up. The car is deadly quiet and music is so clear. I enjoy that alot.

In the foxbody however I'm scared I'll die if I keep the windows up. The pretty much stay down all the time except when they make me roll em up at the drag strip. Uh...Nothings worse than a firejacket/jeans in 104* heat in direct sunlight.

[CKMustangCobra]

There isn't enough difference to measure.

It all depends if you want to hear the radio, wife, etc...

or

the beautiful howling of the winds passing by and the orchestra of tones coming from underneath the hood of a nice, clean, sharp Marauder, ready to pounce the speedo at the flick of your toes.

[Stranger in the Black Sedan]

I enjoy precise temperature and humidity control. Windows up.

[finster101]

Our windows go down?? :eek:

[mrjones]

Come to east TX, with me. You won't care anymore. There will be no debate. I saw 106 on my temp today, going down the freakin' hwy.

And here, it AIN'T a dry heat.