Thanks, that actually makes perfect sense. I have a passing familiarity with R-Values after researching various ways to seal up and re-insulate my attic. Went from an R15 (the house was built in the 80's) to R35-ish with a ton of blown in insulation. HUGE difference in how comfortable the house is.
I could double up the r5 board couldn't I? R10. Of course that effectively doubles the cost of the materials though.
Those little dorm fridges are just so darn cheap though. You can find them for like $40 or less or a nice one, the larger "mini" fridges are $60-120 used.