AC's been running nonstop this summer — when it's time to replace vs. just repair?

[JimmyMechanic]

Our unit is about 12 years old and just needed another repair (capacitor this time, not too bad) but it's the third service call in two years. Compressor and coils are still original.

I keep going back and forth — the repairs individually aren't crazy expensive, but they add up, and I know newer units are way more efficient (SEER2 ratings weren't even a thing when ours was installed). At what point does it stop making sense to keep patching it? Is there a rule of thumb on repair cost vs. age, or did you all just wait until it died completely?

Curious what pushed people here to finally pull the trigger on a new system vs. squeezing a few more years out of the old one.

[handyandy]

I usually tell people not to replace an AC just because it's 10–15 years old. I'd look at the whole picture.

A few things I consider:

• Frequency of repairs. Three service calls in two years starts getting my attention, even if each repair isn't terribly expensive.
• Type of repairs. A capacitor is a wear item and isn't a reason to replace the system. A failed compressor, leaking evaporator coil, or major refrigerant leak is a different story.
• Repair cost vs. replacement cost. A common rule of thumb is that if a repair is 30–50% of the cost of a new system, replacement is worth serious consideration—especially on a unit over 10 years old.
• Performance. If it's still cooling well, humidity is under control, and your electric bills aren't outrageous, there's no reason to rush into replacing it.

At 12 years old, you're kind of in the "start planning" phase. I wouldn't replace it because of a capacitor, but I would start getting quotes so you're ready if the next repair is something major. Replacing it on your schedule is usually a lot less stressful (and sometimes less expensive) than doing it in the middle of a 100° heat wave after a compressor fails.

If it were my system, I'd probably keep running it, set aside money for a replacement, and reassess if the next repair is a compressor, evaporator coil, or another expensive component.