Kate,

thanks for the research. Looks like you covered most of the variables. I have always suspected that driving on the highway with the windows open would be as bad or worse as using the a/c, especially on recirc (vent closed) mode which allows the compressor to work less.

I have also wondered what the effect of drag caused by the rear window is. The old station wagons had rear windows that retracted completely, taking that out of the equation so they probably did a little better. I wish the rear windows of the Escapes could open and eliminate this drag, which at highway speeds has to be huge (driving with the side windows open that is). If you were able to vent at the rear of the car to reduce the pressure inside the car I think the mileage difference would increase with the windows open mileage improving.

I recently removed my roofracks and definitely noticed an increase in my highway mileage. The jury is still out on the city driving - I don't think it would make much difference at lower speed. Although I am looking at my best tank yet on the '06.
Good info. Thanks.