I feel for you Pro2a. Every year just before the cold season starts I have a local HVAC company come over and inspect it. I usually have some repair to make. This year no repair, a replacement. I have to replace my gas furnace. The current one is 17 years old so you may want to have someone come over and inspect yours just to be safe. The HVAC company got me a high effeciency model for just under $3000 installed. I hope it qualifies for the federal tax credit this year. Fortunately I did this early and the furnace is to be installed on Wednesday.