Funny this has been brought up again. I stated last time about friends that use fridges to brumate their snakes and such. They usually put about a 1/4" to 1/2" hole in the door for ventilation.
Lately, I was checking some websites (don't have the URLs) about oxygen content and other environmental qualities inside of refridgerators. It was covering foods and so on, yet seemed to have enough of what it took to control a brumation period for snakes. I honestly think I may go this route next year. Due to some local record breaking cold spells, other factors and so on, I realized that a fridge just may be one good way to control the whole brumation period. I never looked into it this much except a few weeks ago. Looks good enough for me.....