Tesla Motors Club

Let's assume it is 40F outside and cabin temp is set 70F, would it be more efficient to use recirc with AC-on or fresh air with AC-off. I realize recirc with AC off would be most efficient, but the windows get foggy so recirc basically requires AC, at least if using for any extended amount of time.

Any thoughts on what is more efficient? It seems counter-intuitive to run the AC compressor and the heat simultaneously, however, heating 32F outside air up to 70F also consumes a lot of energy.

I'm curious what the community thinks on this.