I bought a house in the cleveland, OH area built in '54. I am considering replacing my furnace, but don't know where to start. I would like to find out some information on the current furnace first, but I cannot locate any info. What I have is a sears (105K BTU??) natural gas furnace. Model #867.762331 serial #H44374855 manuf #SUGF105c602. Any place I can find this information? I do not know if it is original to the house or not. It still works, but my gas bill is huge. Thanks for your help.