It seems so obvious. If you live in an area with a decent winter, you can create a fridge on the outside wall of your kitchen that opens to the elements to create an “ambient air fridge” (AAF). If you’re wondering what you do on an unseasonably warm day, the builder keeps a few jugs of water in a snowbank as an emergency ice source. Living in Vermont, he’s able to use his AAF from mid-November to early-April. Obviously, YMMV in different locales.

DIY Super Energy Efficient Refrigerator – Link