My heat is divided into 2 zones, zone 1 controls the radiators in the basement and zone 2 is the rest of the house. Currently the thermostat in the basement is the old mercury type, and I can't turn it below ~58. The knob simply doesn't turn any lower.
I'm assuming its down there to prevent pipes from freezing, etc. The basement is unfinished, not insulated, only used for storage and laundry.
I would like to get a new thermostat and set it considerably lower than 58. At that temperature it comes on way too often in my opinion. How low can I set it and still be safe? The thermostat itself is in the center of an approximate 15' x 50' basement.