Originally Posted by BigFloyd
Unless you're going to be fermenting more than 2 5-gallon batches at once, the used Craigslist fridge/freezer plugged into a controller outlet box with an STC-1000 still strikes me as the cheapest, easiest and most reliable way to accomplish this. Plus, it requires no modification at all to the fridge. Just plug it in and let the STC do its thing.
If you are just a bit patient, keep and eye on CL and are willing to negotiate, the full-size unit with controller outlet box can be done for under $100.
This is a great idea for less brews. I built my room into my garage to never be removed and designed it for a growing home brewery. Made it big enough for 6-8 fermenters to go at a time, and a shelf for just as much in bottles for conditioning. I'm up to 3 fermenters going at one time, but in the years to come, that will grow. Were I live we have wild weather ( -20 at times in winter and easily over a hundred for most of the summer.) my window air conditioner is actually a heat pump, meaning it will run cooling, or it can run the refrigerant backwards and heat as well. It cost me about $400 new. (Hard to find a new one, let alone a used one)