Looking for some advice here guy's,...I have a propane gas furnace that heats my office and I know the thermostat is not working correctly. Here's the scoop during the day I heat my office with a 23,000 btu (kero-sun) kerosene heater, it can warm this office up to 100% if I keep it going long enough, and at night I turn on the propane furnace, this winter I notice that I have been using a LOT of propane.I notice that the temp gauge on the thermostat for the furnace is way off. I put up 3 out door temp gauge's around the room the other morning and turned on the kerosene heater, after running for 2 hours the temp gauges that I put around the room all read 80 and the temp gauge on the thermostat reads 50, I check the thermostat with a level and it is level, This thermostat is a programable one and is about 25 years old, Do they go bad? for the past few days it has been off anywheres from 20-30 degrees than what the temp gauges that I placed around the room are reading which leads me to think that it is kicking on the furnace premature Thanx kkat