Quick answer: replacing an AC compressor costs about $600–$4,000 installed across three 2026 price guides, and This Old House puts the average at $1,550. It's usually the most expensive repair an AC can need.
What the price guides say
| Source | Installed price |
|---|---|
| Fixr (updated January 2026) | $600–$3,000 |
| This Old House, AC repair (updated March 2026) | $1,000–$3,000+ |
| PickHVAC (May 2026) | $900–$4,000, average $1,800 |
| This Old House, AC compressor (updated August 2026) | Average $1,550 |
Cost by system size
This Old House's compressor figures by size:
| System size | Low | Average | High |
|---|---|---|---|
| 1.5–2 tons | $700 | $1,050 | $1,400 |
| 2.5–3 tons | $900 | $1,500 | $2,100 |
| 3.5–4 tons | $1,100 | $1,600 | $2,100 |
It puts labor at about $113 an hour or an average flat fee of $600. The other guides' ranges reach higher, up to $4,000, so treat this table as typical rather than a ceiling.
Signs the compressor has failed
- The outdoor unit runs, but the air inside stays warm
- The outdoor unit hums, clicks or struggles to start
- The breaker for the outdoor unit keeps tripping
- Loud grinding, banging or rattling from the outdoor unit
The same signs can come from much cheaper parts. A compressor that won't start is sometimes a failed capacitor or contactor, so ask the technician how they ruled those out.
Check the warranty first
The compressor may still be under the manufacturer's warranty, which can leave you paying mainly for labor. Find the paperwork or the registration before the visit. This Old House warns that mismatched parts, skipped maintenance or an unlicensed technician can void a warranty.
Repair or replace the AC?
This Old House suggests a repair makes sense if the system is under 10 years old and the repair is under $1,000. If the repair bill is more than half the price of a new unit, or the system is over 10 years old, replacing it often gives better value. Compare with what a new system costs in Savannah.