AC Replace vs. Repair
An aging AC breaking down forces a fast decision: pay for the repair, or put that money toward a replacement instead. The repair is almost always cheaper today; the question is whether it is cheaper over the years you actually plan to keep the system.
At your inputs, repairing and keeping the current AC costs $1,100 less over 10 years.
| Replace the AC now total cost over the horizon | $13,000 |
|---|---|
| Repair and keep the current AC total cost over the horizon | $11,900 |
Breakeven: The higher upfront cost is offset by year 12.8, after which replacing now stays cheaper.
- This uses planning estimates you entered, not a contractor quote or guaranteed savings.
- A lower calculated cost does not measure comfort, outage tolerance, noise, installation constraints, or incentive eligibility; weigh those separately.
What this also tells you: Even if your annual costs are 20% higher or lower than entered, the same option stays cheaper, with the advantage ranging from $1,900 to $300.
This is a planning estimate based on your entries. It does not size equipment, determine electrical or building-code compliance, verify incentive eligibility, or replace a contractor quote or professional energy audit.
Why this decision comes up
AC failures rarely happen on a homeowner's schedule, and the technician standing in front of you with a repair estimate is not the person best positioned to tell you whether replacement is the better long-run move. That comparison belongs to you, with your own numbers.
How this is calculated
Both paths are priced as upfront cost plus annual cost, carried across your ownership horizon. The repair path's upfront cost is the repair bill itself; its annual cost should reflect your current system's actual efficiency, which is often lower than a new unit's.
A worked example
With the defaults (replace: $6,000 upfront, $700/year; repair and keep: $900 upfront, $1,100/year; 10-year horizon), replacing totals $13,000 against $11,900 for repairing, so repairing wins by $1,100 at these defaults. Raise the repair cost to $2,500 and the ranking flips, since the smaller upfront gap no longer offsets ten years of higher annual cost.
Common mistakes
The most common mistake is treating the repair estimate as the whole cost of the "keep it" path and ignoring the annual efficiency gap, which compounds over a long ownership horizon even when the repair itself is inexpensive.
Limitations
This does not predict whether or when your current system will need another repair. If you expect a second failure within your ownership horizon, build a reasonable estimate of that cost into your annual figure for the repair-and-keep option.
Common questions
The repair is so much cheaper, why would replacing ever win?
An older AC typically costs more to run every year than a new one, and it is more likely to need another repair soon. Over a long enough ownership horizon, those two facts can outweigh a repair's lower sticker price.
What annual cost should I use for the repair-and-keep option?
Your current cooling cost, plus a reasonable allowance for the chance of another repair during your ownership horizon if you expect one. If you are not sure, your current utility bill alone is a defensible starting point.
Is there a repair cost where replacing becomes obviously better?
Yes. Use the HVAC repair threshold tool to solve for that exact number directly instead of testing repair costs one at a time here.
Is there a rule of thumb, like multiplying the AC's age by the repair cost?
Some contractors use a heuristic like age in years times repair cost compared against a flat dollar figure to suggest replacement. It is a rough shortcut, not a real cost comparison, since it ignores your actual annual operating costs and how long you plan to stay. Running your real numbers through this tool gives a more reliable answer than any flat rule.
Does an old refrigerant type change this decision?
If your AC uses a phased-out refrigerant like R-22, a repair that requires adding refrigerant can cost far more than a modern-refrigerant system's equivalent repair, or the refrigerant may be hard to source at all. Reflect that in the repair cost you enter rather than treating it as a separate factor.