The last thing I'd use is the LP furnace. Electric heat if you really feel you need to heat it.
LP is cheaper? I'm curious. How do you figure? Are you going to be running off of one of those large 100lb cylinders or something? Around here it costs about $18 to fill a 20lb LP cylinder. That makes for 430,000 BTH so about 24,000 BTU for a dollar. Electricity costs about $.12 per kWh. A kWh is about 3,400 BTU so about 27,000 BTU for a dollar. Not only that, the electric heater will be 100% efficient, the LP furnace will blow lots of BTUs out the exhaust.
