Note that this is only an advantage in cooler months, and does work against cooling your home in hotter weather. In principle it seems like we could could build our refrigerators into an outside wall (like iceboxes once were) and then expose the coils in summer, and enclose them in winter.
Not really, efficienty aside the heat it puts out the back is coming from inside the fridge... Which is coming from the room housing the fridge. So over the course of a day it should be neutral.
