Kegerator storage temp question

I live in MN and I have my kegerator on my porch, which is a 3 season porch and can get pretty cool as it is not insulated. Should I move it indoors for the winter months? The other night I went out there and the temp inside the kegerator was 33 degrees. I am worried that when it gets to be in the negative digits temp-wise, my beer will freeze. What could I do to leave it out there as moving it is a pain. If I have to move it in that is fine, but if there is a way I could keep it out there, that would be the best case scenario.

A second temp controller running a heater inside the fridge would be your other option. My guess is the electric usage might be similar to the summer time running it as a chiller.

I use a heater like this in my fermenation chamber…

http://www.walmart.com/ip/Lasko-Product ... r/16503222

I have a single stage controller and run the heater in the winter and the freezer in the summer.