Originally Posted by BSBrewer83
I know this doesn't answer your question but one way to avoid all of this is to buy a cheap freezer/fridge on craigslist and get a temp controller. I use this setup along with the ferm wrap to maintain exact temps in my chest freezer.
If that doesn't work, you could go "brewguyver" with a dual stage controller, fan, towel, aquarium heater, thermowell, and (optional) pond pump.
Assuming you have low humidity where you are in AZ, the towel gives you swamp cooler effect (don't fully submerge carboy, the fan accelerates, the aquarium heater heats the water, pond pump circulates for more even heating, and the thermowell is so you don't short out the controller probe.
You *could* do it without a controller, but it'll be tough to avoid those temp swings with out it.
Oh - one last thing - you need a nice, reliable GFCI.