We'll be deciding soon on which contractor to go with. However, all of my estimate so far includes replacement of our propane furnace with a new 80% propane furnace. The current 80% Bryant propane furnace is about 17 years old and is functioning properly. If this is the case, would I not be able to just add on a heat pump to my existing system? Would cost savings not be significant by doing so? Or is it a question on the combined efficiency of the system? I was hoping to spend about $ but it looks like it will be 3x my planned budget.