DIY Super Energy Efficient Refrigerator

Shade of Green: 100-year old pine tree

Items Needed: Stack of 2x4's, 4 sheets of 2-inch foamular "pink board," 4 sheets 1/2-inch CDX plywood, enough cedar tongue-in-groove paneling to cover the inside of your framed walls (exactly how much will depend on the size of your "fridge"), 2 small 24v computer fans, 1-3/4-inch hole saw, nails, general carpentry tools.

Why this Hack: Because you live in the north. Because it drives you nuts that you're using electricity to chill your food when it's 20 below outside. Because you're committed.

Heart of the Hack: The idea is simple, though the execution is a bit more complicated. Basically, you're building an insulated box that's going to attach to the outside of your house (preferably in the kitchen area, and preferably to the exterior of an opening that already exists.

The author's AAF (Ambient Air Fridge) fits snug against the outside of a doorway that leads to a seasonal porch off his kitchen. During the warmer months, the AAF is detached for ingress and egress (pretty fancy words for a hack, eh?). It's the ideal size in the ideal location. Your layout and particulars may demand a greater degree of hackishness.

Whatever size you end up with, you want an airtight box that is insulated all around with pinkboard. First, you'll want to frame "walls" for your AAF with the 2x4's, using a standard two-foot-on-center framing pattern. Then, fill all cavities with pinkboard and sheath the exterior with your plywood. The interior gets the cedar paneling, installed with six-penny finish nails.

At this point, you can drill two 1-3/4" holes in the box, one on each side. Drill one at the bottom, and one toward the top. Then, fit two small fans into the holes (Canon makes 24v fans for use in computers). Connect these to a thermostat, and you've got automatic temperature control! (In our next hack, we'll create a solar-powered ice-maker). The bottom will usher in cold air, and the top will expel warm air.

Getting these wired and working properly is the hardest part of this hack, though the carpentry skills necessary to make the box are rudimentary. If in doubt, hire an electrician to help you wire the fans. Once the box is constructed, attach it to the exterior of your opening with 3-1/2" galvanized screws.

The author has been using his AAF for the past three winters, from mid-November to early-April. He keeps a few jugs of water in the snowbank as an emergency ice source during warm spells, but during normal Vermont winter temperatures, his AAF holds at about 40. That's just right for beer, the nutritious food he lovingly provides to his family.

Handy Tips: If the whole fans/thermostat game seems too complicated, use the super hack method of (clean!) socks stuffed in the holes. When the fridge gets too warm and the outside temp is below, say, 30, pull the socks. If there's a skim of ice on your milk, plug the holes.