I have an old Lennox Pulse Furnace from 1994 that is still running like a charm. 23 years is absolutely fantastic. The only maintenance done on it was when I replace that little round filter ever 7 years. It got really cold last week and I started wondering what I would do for a replacement. What is your opinion? I only use it for backup heat from 35 degrees and lower. HP for 35 degrees and up. Are all propane brands about the same? Or is there a "leader" so to speak? I don't think I want the newest technology. Heck, would I be better off with electric heat strips and just eliminate the propane furnace once it dies?