Indoor Climate
How Long Do AC Units Last? Lifespan by Type and When to Replace
A central air conditioner typically lasts about 12 to 17 years, a heat pump 10 to 15 years, and a window unit 8 to 10 years. Climate, maintenance and installation quality move those numbers more than brand does. The $5,000 rule (age times repair cost) is a useful first filter for repair versus replace, but not a final answer.
Typical lifespan by equipment type
| Equipment | Typical lifespan | Notes |
|---|---|---|
| Central air conditioner | 12–17 years | Shorter in hot, humid or coastal areas |
| Air-source heat pump | 10–15 years | Runs year-round, so more hours than an AC |
| Ductless mini-split | 12–20 years | Inverter units run gently; flare joints are the weak point |
| Geothermal heat pump (indoor unit) | 20–25 years | Ground loop can last 50 years or more |
| Window air conditioner | 8–10 years | Sealed system, rarely worth repairing |
| Portable air conditioner | 5–10 years | Depends heavily on use and drainage |
| Gas furnace | 15–25 years | Heat exchanger condition sets the end of life |
| Ductwork | 20–30+ years | Flex duct degrades faster than sheet metal |
| Thermostat | 10+ years | Usually replaced for features, not failure |
These are typical service-life ranges, not guarantees. Plenty of systems pass 20 years; some fail in under 10.
What shortens or extends an AC's life
- Climate and run hours: a unit in Phoenix or Houston may run three times the hours of one in Seattle.
- Salt air: within a few miles of the ocean, condenser coils and fins corrode much faster. Coated coils help.
- Installation quality: a poor vacuum, wrong charge or undersized ducts stress the compressor from day one. See how refrigerant charge is verified.
- Sizing: oversized units short-cycle, adding start-up wear. See AC short cycling.
- Maintenance: clean filters, a clean outdoor coil and a clear condensate drain are the cheapest life extensions available. The filter guide covers change intervals.
- Electrical stress: failing capacitors and contactors, frequent power surges and low voltage all wear the compressor.
The $5,000 rule for repair versus replace
A widely used shortcut multiplies the system's age by the repair cost.
Age (years) × Repair cost ($) > 5,000 → consider replacement
Age (years) × Repair cost ($) < 5,000 → repair is usually reasonable
Examples: a 6-year-old system needing a $400 fan motor scores 2,400, so repair. A 13-year-old system needing a $2,000 coil scores 26,000, so replacement deserves a serious look.
The rule is a heuristic, not an engineering standard. It does not know about your warranty, refrigerant type, efficiency, comfort problems or how long you plan to stay in the home. Use it to decide whether to ask for a replacement quote, not to make the decision on its own.
Other factors that tip the decision
- Refrigerant: an R-22 system with a large leak is usually a replacement candidate because R-22 is no longer produced. See refrigerant types.
- Compressor failure: on a system past about 10 years, a new compressor often costs a large share of a new system. Details in AC compressor replacement cost.
- Warranty: many parts warranties run 10 years if the unit was registered, which can make a major repair far cheaper.
- Efficiency gain: replacing a 10 SEER unit with a current 15 SEER2-class system can noticeably cut cooling costs. Run the numbers with the SEER rating guide.
- Comfort problems: if the house was never comfortable, replacement is a chance to fix sizing and ductwork rather than repeat the old mistakes.
Signs an AC is near the end
- Repairs every season, especially repeated refrigerant top-ups.
- Rising energy bills with no change in use.
- Uneven cooling and higher indoor humidity than it used to manage.
- Loud compressor starts, rattles or a burning smell (switch off and call a technician for any electrical smell).
- Heavy corrosion on the outdoor coil or cabinet.
None of these alone means replacement, but several together on a system past 12 to 15 years usually do.
Getting the most years from your system
Change or clean filters on schedule, keep 2 feet of clearance around the outdoor unit, rinse the condenser coil gently each spring, keep the condensate line clear, and have a technician check electrical parts and refrigerant performance every year or two. Small items such as a capacitor replaced before it fails can prevent a compressor failure later.
What replacement involves
If you decide to replace, a few points protect the investment. Ask for a load calculation rather than matching the old unit's size, since many older systems were oversized; the AC tonnage calculator gives a sanity check. Replace the indoor coil with the outdoor unit so the pair is matched and rated together, and so the coil suits the new refrigerant. Have the installer check the ductwork for leaks and undersized returns, because new equipment on poor ducts rarely meets its rating.
New systems sold from 2025 use A2L refrigerants, which means a new line set or a careful flush and pressure test of the old one, and in many cases a refrigerant leak sensor. Make sure the quote states the refrigerant, the matched model numbers, the SEER2 rating and the warranty terms, and register the equipment with the manufacturer promptly so the full parts warranty applies.
Frequently asked questions
Is a 15-year-old AC worth repairing?
For a small repair, often yes. For a major repair such as a compressor or coil, replacement usually makes more sense at that age, especially on R-22 equipment.
Do AC units last longer in cooler climates?
Generally yes, because they run fewer hours each year. Coastal salt air can offset that advantage.
Should I replace the furnace and AC together?
Often it makes sense if both are near the end of their life, because the indoor coil, blower and outdoor unit are designed to be matched. If the furnace is young, replacing only the AC and coil is fine.
Last reviewed 2026-10-28