I have the same problem here in NC. Summertime its 100 deg in my shop, right now im struggleing to keep it above 50 deg, ( its in the 30s outside) I have a Stanley elect heater i run throut the winter & it has kept things above freezing so far in the last 10 yrs or so. One thing i want to mention is the Fromeco battery information says NOT to charge them below 50 or 55 Degs. I store all my gas & glow planes out there along w all my building supplies & to date I have not had any issues. I miss my basement i had when i lived in Pa!...Gene