Like others have said not a problem if only cold at night. Plus you will be living in the unit so the heat will be on at night and it will warm up nicely in the day. As long as it is warming up during the day you are good even to leave the unit even unheated. I have done it many times down to -10C or 14F with no problems. The real problem only happens when it hard freezes and then not fully thawing during the day.
I like to leave the hot water pilot on (if you have one)or leave the tank on till bed then shut off and it will stay warm all night.