I am using 2 Love Controllers. The one on the freezer side just turns the compressor on and off, just like the original thermostat, but with a greater degree of accuracy and range. The one on the refrigerator side controls 2 AC fans (push and pull) and a small 200 watt heater. It is designed to be a fermentor (I have to get going on a new brew) in which I have been able to attain 71 degrees with no problem. I have had as much as a 30 degree temp difference between the 2 sides.