What do you set your house heat at when leaving for winter?

My summer home is at 9,000 ft in the Colorado mountains, where it gets down to -20 F. When I leave for the winter 6 months everything is shut off, no heat, no water, no elect, & RV antifreeze pumped into all the pipes, drains, traps. Been doing that for 8 yrs and no ill effects yet. 50% of that area is summer only residents and they all do the same.