[77newell]

Hey Aragona: welcome to the Michigan big chill, aren't we having fun. You probably still have a thermostat with points and a coil. If so, then the advice of Forest is a possibility as is getting a small file and cleaning the points. As the air temperature cools the points even when "closed" are put under increasing pressure which may at some point cause them to send enough current to the furnace to start it. In any case, every points type thermostat I've been around will make a ping sound when it gets cold enough to call for heat. If you don't hear the ping until you are freezing then the thermostat coil is toast and Keith's suggestion is the way to go. If you hear the ping and then later the furnace kicks in you could try cleaning the points. You can test the points by taking a short piece of wire and jumping across them after they have closed. If that kicks the furnace on you know cleaning the points will probably solve it, otherwise toss it.