brewers edge controller 11 and space heater question

I am using a controller 11 and space heater to heat the freezer side of a side by side fridge in order to make a fermentation chamber. I live where it gets pretty cold at night. So far, with adding additional insulation, the set up can only get to 63 F. I want 69 F. Could I add a second space heater to the controller? Basically wondering the idiosynchracies of this unit, like if the controller would just split both heating pads to equal, renderring this pointless Thank you