We will be selling our TDI diesel back to VW soon and hopefully taking delivery of the currently shipping Model 3 by the end of Sept.. Our TDI Sportwagen with aftermarket window tint uses between 8 to 10% more fuel when running the air conditioner. When traveling by myself, I lay the windshield sun shade light grey side up on top of the fairly large black dashboard. Doing this dramatically reduces the interior reflected heat and reduces the temperature of the air coming from the vents while venting outside air though the open sun roof. I use the pop up mode of the sun roof which does not seem to increase drag or the sound level much. While driving in a areas with low humidity with outside temps below 80F, I am very comfortable using this method. In very cold weather the TDI fuel mileage is not effected after the engine reaches operating temperature. From what I have read, there are some things one can do to slightly improve cold weather model 3 efficiency (which can take quite a hit!) but would a flow though ventilation method work on a model 3 at temps below 80F? Since the model 3 doesn't have an opening sun roof, is there enough air flow while using the vent fan to keep the interior temp comfortable with outside temps below 80F?