How Old Is Too Old to Save?

If your furnace or air conditioner is old, that alone does not mean it needs to be replaced. Contractors quoted in a recent industry piece say condition matters more than age. A well-maintained system can run strong at 35 years or more, while a neglected 10-year-old unit can already be failing. One contractor said he's kept systems running to about 50 years old, since older equipment tends to be mechanically simple and built from heavy steel with fewer electronics to break.

That said, contractors point to around 15 years as the point where the repair-versus-replace conversation starts to shift, especially if a system needs major work. Things that push the decision toward replacement include a failed compressor, a cracked heat exchanger, water damage, or a refrigerant leak in a system that uses R-22, an older refrigerant that's now expensive to buy. Parts availability matters too — cheap, common components like capacitors are usually worth fixing, but costlier or harder-to-find parts change the math. When a repair costs hundreds of dollars but everything else on the unit is just as old, contractors say the money may be better put toward a new system, since payback on a patched-up repair can be poor.

None of this is automatic, though. Contractors say there's no fixed cutoff age, and the decision to repair or replace ultimately belongs to the homeowner — except when a repair would be unsafe, which is where some contractors say they draw a firm line.