We found out that our furnace was broken on Friday night. It is winter time. It was the first time we tried to bring up the unit after long summer. It is a 35+ years old unit. Probably not worth to repair it. Called home depot and scheduled an estimate with Delta Mechanical. Justin came and game me a detailed explanation of what the options are, scope of works involved and pricing of all options. I am an engineer and always interested in how stuff works. Asked a lot of questions. It is kind of a training session for me. Apparently Justin is a pro. He explained to me there was a pilot flame in the old unit. Of course I want to see it. Justin came down to his knees, opened dusty cover of the old furnace, tried to show me the pilot flame and then we found out that pilot flame was gone. It seems we found the problem. Maybe I don't need to purchase a new unit. Then Justin helped me ignite the pilot flame. After that, my old furnace started working again. Yay! After that, Justin also showed me some of the areas that potentially could cause problems down the road since they are so old and how to DIY fix them. Now my furnace is running and I learned how to fix some easy problems. I am super happy. Don't know how long this old furnace will last. Keep fingers crossed.