Most central air conditioners last 15 to 20 years. ENERGY STAR suggests considering replacement after 10, which is about efficiency rather than failure. The real deadline is often the refrigerant: an R-22 system is at least 16 years old now, and a single leak can cost more to refill than the unit is worth.
Lifespan by type of air conditioner
The 15 to 20 year figure is for a central split system, which is what most US homes have. Other formats sit in quite different places.
| Type of air conditioner | Typical lifespan | Why it lands there |
|---|---|---|
| Portable | 5 to 10 years | Everything packed into one small chassis, no servicing |
| Window unit | 8 to 10 years | Same problem, slightly better airflow |
| Ductless mini split | 10 to 20 years | Wide range, installation quality decides it |
| Central split system | 15 to 20 years | The figure people mean by this question |
| Evaporative cooler | 15 to 20 years | Few moving parts, dry climates only |
| Geothermal heat pump | 15 to 25 years | Buried loop outlasts the indoor equipment |
Central system range per Carrier, which puts a well maintained unit at 15 to 20 years and a neglected one at 10 to 12.
Maintenance moves these more than anything else on the list. Carrier puts a well maintained system at 15 to 20 years and up to 25 with diligent care, while a neglected one can fail around the 10 year mark. That is a 15 year spread created by whether anyone cleaned the coils.
Your AC has two lifespans, not one
This is where most answers to this question quietly contradict each other. Manufacturers say 15 to 20 years. ENERGY STAR says consider replacing after 10. Both are right, because they are answering different questions.
- Mechanical life is how long the machine keeps making cold air. That is the 15 to 20 years.
- Economic life is how long it makes sense to keep it. That ends earlier, and it is what ENERGY STAR’s 10 year mark is pointing at.
A 14 year old unit that still cools is not automatically worth keeping. It is likely running at 10 SEER against 14.3 SEER2 minimum on anything new, which is roughly a third more electricity for the same cooling. It has no warranty left. And it is one compressor failure away from a bill that buys most of a new system.
So the honest answer to how long an AC unit lasts is 15 to 20 years mechanically, and somewhere between 10 and 15 years economically, depending on your electricity rate and how hard you run it.
The refrigerant test almost nobody mentions
There is a third clock, and it has nothing to do with your unit’s condition. What refrigerant it was built for now decides what a repair costs.
| Refrigerant | Unit built | Refrigerant cost | What a leak means for you |
|---|---|---|---|
| R-22 Freon |
2010 or earlier 16+ years old |
$90 to $250 per lb avg about $150 |
$540 to $3,000 of refrigerant alone on a 3 ton system. Treat it as a replacement decision. |
| R-410A Puron |
2010 to 2025 | $40 to $75 per lb | $240 to $900 of refrigerant. An ordinary repair. Production drops to 15% of today by 2036. |
| R-454B, R-32 A2L, low GWP |
2025 onward | Current supply | Nothing to worry about. Full service life ahead of it. |
Check the data plate on your outdoor unit. It names the refrigerant. A 3 ton system holds 6 to 12 pounds when fully charged.
Read the R-22 row again. The US stopped manufacturing new R-22 residential systems in 2010 and banned production and import of the refrigerant itself on 1 January 2020. Only recovered and reclaimed stock remains, and it averages around $150 per pound with a range of roughly $90 to $250.
A three ton system holds six to twelve pounds. So a system that loses its charge needs $540 to $3,000 of refrigerant alone, before any labour or the repair that caused the leak. The same job on an R-410A system costs $240 to $900 in refrigerant.
If your unit runs on R-22, it is 2010 or older and its economic life is over even if the compressor is fine. The first significant leak is a replacement decision, not a repair decision.
What about the 2025 refrigerant change?
New residential systems moved to low GWP A2L refrigerants such as R-454B and R-32 from 2025 under the AIM Act. R-410A is being phased down to 15% of current production by 2036, which is gradual enough that an R-410A system bought today has a normal service life ahead of it.
One thing did change in your favour. EPA’s final rule of 26 May 2026 reversed the earlier ban on installing pre-2025 R-410A equipment after 1 January 2026, so leftover R-410A stock can still be fitted while it lasts. New York codified the original deadline, so that state is an exception.
What shortens an AC unit's life
- Skipped maintenance. A dirty coil makes the whole system work harder, and it is the single biggest controllable factor. Carrier puts an unmaintained system at 10 to 12 years against 15 to 20 maintained.
- Salt air. Coastal installations corrode the condenser coil considerably faster. If you are within a mile or two of the ocean, expect the lower end of every range on this page unless the unit was specified for coastal use.
- Oversizing. A unit too large for the house short cycles, switching on and off repeatedly. Every start is hard on the compressor, and it dehumidifies poorly at the same time.
- Run hours. A system in Phoenix runs several times the hours of one in Seattle. Lifespan in years is really lifespan in run hours wearing a calendar disguise.
- Bad installation. Wrong charge, poor airflow or an undersized line set shortens life from day one and is invisible until something fails.
Repair or replace, decided by age
Two rules are in common use and they mostly agree. Carrier’s is that if a repair approaches 50% of the cost of a new system, replace. The other, quoted widely by contractors, is to multiply the repair cost by the unit’s age and replace if the result exceeds $5,000.
Worked through, on a $7,000 replacement:
- A $400 repair on an 8 year old unit: 400 x 8 = 3,200. Repair.
- A $400 repair on a 14 year old unit: 400 x 14 = 5,600. Replace.
- A $1,200 compressor on a 12 year old unit: both rules say replace.
The rules break in one place. Neither accounts for the refrigerant, so both will tell you to repair an R-22 system that you should not repair. Add that check first.
What replacing it would cost
Age alone does not tell you whether to act. Put your tonnage, efficiency target and home size in and see the installed number, then weigh it against the repair quote in front of you.
Free tool
AC Replacement Cost Calculator
Installed pricing by tonnage, SEER2 and home size, so you can hold a real replacement number against the repair quote in front of you.
If you are weighing a heat pump instead of a like for like swap, our guide to whether an AC or a heat pump is cheaper to run works through the running cost side.
Quick answers
Is a 15 year old AC unit too old?
Not automatically, but it is at the point where you should stop paying for significant repairs. It is out of warranty, likely well below current efficiency minimums, and any compressor or coil failure is a replacement decision.
How do I find out how old my AC unit is?
The manufacturing date is encoded in the serial number on the outdoor unit’s data plate. Most brands put the year in the first four digits or as a two digit year after a letter code. If the plate lists R-22 as the refrigerant, it is 2010 or older.
Does an AC last longer if you run it less?
Generally yes, because wear tracks run hours rather than calendar years. That is why an identical unit lasts longer in a mild climate. Turning it off entirely for long stretches is not a win though, since seals and the compressor prefer regular use.
How long does a window AC unit last?
About 8 to 10 years, and a portable unit 5 to 10. Both run far shorter lives than a central system because the compressor and coil are packed into a small chassis with less airflow and no professional servicing.
Can an AC unit last 25 years?
Yes, with consistent maintenance and a mild climate, though it is uncommon. Whether you would want it to is another question, because a 25 year old unit is using a great deal more electricity than a new one for the same cooling.
How often should I service my AC to reach 20 years?
Once a year, before the cooling season, plus filter changes every one to three months. That single annual visit is the difference between the 10 to 12 year outcome and the 15 to 20 year one.
Sources
- ENERGY STAR, When is it time to replace?
- US EPA, AIM Act HFC phasedown, and the final rule of 26 May 2026 on R-410A equipment installation
- Trane, R-22 phase-out timeline, new equipment ended 2010, refrigerant production banned 1 January 2020
- Carrier, How long do air conditioners last
More short answers like this one: browse all Calcxi answers.
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