I have a Lennox Pulse furnace that is 19 years old and it has quit working. Had the Lennox repairman out and he concluded that a new unit is in order. He was unable to detect the reason why it isn't working. Here's my problem. I know very little about furnaces and he offered three alternative ways to go. The a/c unit is the same age as the furnace but is working fine now.
1) Replace just the furnace and keep the old a/c until it dies. Cheapest alternative.
2) Replace both the gas furnace and the a/c unit.
3) Replace the whole system with a Heat Pump with a gas furnace for backup in extremely cold whether. We live in Central Nebraska and it gets coooolllddd out here.
The third option would be the most expensive but I understand the heat pump is considerably more efficient and would pay for itself in a few years. I would appreciate any advice as to which choice I should make. Thank you!