I wanted to post an update to the crappy little, used upright freezer that I converted to an ultra-efficient refrigerator by adding a cheap temperature controller to throttle back the freezer.
It has been the simplest and most successful of hacks, with regards to efficiency improvement related to time and effort of the hack.
It used very little energy, and works well. There has always been a condensation problem/feature, which I can live with, since produce last much longer in a humid-cold environment than a dry-cold environment.
However, my extraordinarily sloppy temperature control assemblage fell off the top of the Freezerator and was dangling by live wires. I had no problem, carefully duck-taping the electrical mess back on the top of the Freezerator.
However, I was very surprised to find out the next day, that my thrifty little refrigerator had reverted to it's true nature and had become a Full-On freezer during the night. Turns out that fresh produce doesn't like to be frozen, and neither do jars of soup.
After the mess was cleaned up, I built a sanitary version of the temperature controller, now that I was convinced by the nearly 5 years of trouble free service.
So now, it's just great.
It could still use lights that come on when the door is opened.
Best,
-AC_Hacker