Good morning,
I got to thinking about this on the highway the other day as I was deciding whether to open a window or turn on the A/C....
I was wondering what was a more fuel efficient way to cool down - to open a window which creates drag; or turn on the A/C and create load on the engine?
A friend from Florida said the concensus of local opinion down there is it's more fuel efficient to turn on the A/C (creating load) than to open a window (creating drag).
What do all of you think?

 

At highway speeds the AC would be more efficient.

 

didnt they do this on mythbusters and find out that it is more fuel efficient to have the windows rolled down than run the a/c. but the difference was not much, maybe at most about 3-4 miles for a full tank of fuel.

 

Yes, they did that.....and a fully loaded SUV with the windows down ran for like an extra 40 miles I think....

The truth is....it really doesnt matter....its all about preference....because every vehicle will perform differently....