How many years should an HVAC system last? (furnace, AC, heaters)

[kentuckydad95]

Our home is around 12 years old and so is the HVAC system. It's a split system, the AC outside (of course) and the propane-run heating system in the attic. When should we start planning on getting a new system? We haven't had any problems yet (knock on wood). Are the systems made to last 20 years or so?

[arctichomesteader]

Well, I grew up in a house with the original 19th century boiler, long ago converted to burn oil from coal...still going strong now I believe...

But most modern systems won't last that long. At 20 years, I'd have some money set aside and plan for it to die eventually...always have a backup heat source in case it dies unexpectedly.

[Barking Spider]

Im guessing that the service life in Kentucky is probably similar to East Tennessee, so here is what I find in my area.

Electric heat pumps last about 12 - 14 years.
Gas and propane forced air heaters last 16 - 20 years.
Split a/c units with gas heat will last about 16 years.

Obviously the life span can vary a lot depending on the use, maintenance, quality of the equipment in the first place, and just plain old luck.

The outside unit will usually have the compressor go out. Sometimes the inside coil will need to be replaced too.
The gas furnace will have the blower bearings go out, the burners and controls will wear out, and the heat exchanger will finally rust out. While you can replace the blower and burners and control parts easily, when the heat exchanger goes, its time to replace the entire unit.