I have a CO detector in place (actually two) for monitoring.Fyrfightr wrote:New furnaces with electronic ignition usually have stainless steel heat exchangers. Older standing pilot furnaces have carbon steel heat exchangers. We see those rusted out and putting CO into the house on the fire dept. I run on.
I would have your heat exchanger tested/inspected. I replaced my standing pilot furnace with a new 95% efficient furnace several years agomand it paid for it self in 2 years.
I did the calculations several years ago - a furnace of my type is about 65% efficient. It would take not two years but over a decade to pay off the difference, and most modern furnaces have heat exchangers with a lifetime MTBF of 18 years. Those 8 years of savings after paying itself off would fall short of purchasing a new heat exchanger or furnace (usually most people replace the furnace).
The payback for adding insulation was far better, so I put the money there. Once I get close to retirement, I will replace the furnace and ride it out until I leave the house. Twenty years should cover it.