I don't heat mine either. Its at 8500 ft elevation in the Colorado mountains where winter temps often get to -20 F. Its got a propane furnace, but I don't feel comfortable leaving the propane on while I'm gone for 6 months. It would likely empty the tank and run out of gas before winter was over, even at a low temp setting.
I just shut everything off, drain all the pipes & water well; and then fill the pipes & drains with RV antifreeze. This has worked well for the last 6 yrs and I've had no other effects from no heat.
