I do have a portable heater that has temperature controls and it sets on the floor by the barrel closest to the door. I haven’t turned it on yet this year but it did keep me above freezing last winter.
There is the answer, just hadn’t read far enough. What is your altitude, and the normal day time high in January.
I’m at 4100 feet here. I’m guessing my normal average daytime highs in January are in the 30’s. If I have a pogonip come through it is generally in the teens and occassionally it will get into the 40’s.