How Long Does an AC Last?
A central air conditioner lasts 15 to 20 years — 12 to 17 in a hot, heavy-use climate. The signs it's near the end, and when age alone says replace.
A central air conditioner lasts 15 to 20 years (NerdWallet), and 12 to 17 years for a well-maintained unit under average demand (Bob Vila). Where you live decides where in that range you land: a system in a mild climate can run past 20, while one that cools a house in Phoenix or Houston for eight months a year is often done by 12 to 15.
ENERGY STAR treats the 10-year mark as the point to start planning — not because the AC will fail at 11, but because 10 years is roughly the midpoint of its life and the efficiency gap to a new unit is already wide.
How long does a central air conditioner last?
15 to 20 years for central AC, less for units that work harder:
| System | Typical lifespan | Notes |
|---|---|---|
| Central air conditioner | 15–20 years (12–17 with heavy use) | The compressor is the part that ends its life |
| Heat pump | ~10–15 years | Runs year-round, so more hours on the compressor |
| Ductless mini-split | ~15–20 years | Similar to central AC; each head is replaceable |
| Window unit | Shorter | Almost always cheaper to replace than repair once out of warranty |
Sources: NerdWallet, Bob Vila, ENERGY STAR.
What shortens an AC's life?
| Factor | Why it matters |
|---|---|
| **Hot climate + long cooling season** | An AC in the desert Southwest simply runs three to four times the hours of one in New England ([Bob Vila](https://www.bobvila.com/articles/how-long-does-an-air-conditioner-last/)) |
| **Skipped maintenance** | A yearly service catches low refrigerant, a weak capacitor, or a dirty coil before they overwork the compressor |
| **Dirty filter or coil** | Restricted airflow makes the system run hotter and longer for the same cooling — change the filter every 1–3 months |
| **Oversized unit** | Short-cycles — starts and stops repeatedly — which is the hardest duty on the compressor and its start components |
| **Running low on refrigerant for years** | A slow leak left unfixed lets the compressor run hot and starved, and that is what kills it early |
| **Coastal salt air** | Corrodes the outdoor condenser coil; homes near the ocean often replace sooner |
What happens to an AC as it ages?
- Years 1–10: keep it running. Anything that fails is a cheap part — a capacitor ($80–$400), a contactor, a fan motor.
- Years 10–15: the ENERGY STAR checkpoint. The first expensive failures show up here — a leaking coil, or the compressor. Watch the electric bill and how evenly the house cools.
- Years 15–20: replace on your own schedule, in spring, before it quits during a July heat wave and you are paying emergency rates with no time to compare quotes.
- Years 20+: borrowed time. If it is an R-22 system — most units installed before about 2010 — a refrigerant leak is effectively the end: the EPA banned R-22 production in 2020, so a recharge now costs far more than it is worth.
When should you replace an AC instead of repairing it?
Any one of these points to replacement:
- The repair quote is half the price of a new unit or more (NerdWallet).
- Age × repair cost is over $5,000 — a $500 repair on an 8-year-old unit is $4,000, worth doing; the same repair at 12 years is $6,000, and points to replacement.
- The compressor has failed and the unit is past about 10 years.
- It runs on R-22 and has developed a leak.
- Bills are climbing and the house cools unevenly despite a recent service.
How do I find out how old my AC is?
The rating plate on the outdoor unit — a metal label on the side of the condenser, near the refrigerant line connections. Many list a plain "Mfg Date"; if not, the date is in the serial number, and the format is brand-specific. Decode it with our HVAC age tool — it reads Goodman, Carrier, Lennox, Trane, York and more — or read the printed date directly.
How to make an AC last longer
- Book a yearly service before cooling season — it is the single biggest lever on compressor life.
- Change the filter every 1–3 months. A clogged filter is the most common reason an AC runs hot. The right size and MERV rating matters too.
- Keep the outdoor unit clear — two feet of space, no grass clippings or cottonwood packed into the coil, and hose it down gently once a year.
- Fix a refrigerant leak promptly instead of topping it up each summer — running low is what wears the compressor out early.
- Don't set the thermostat lower than you need. Every degree is more runtime, and runtime is what the lifespan is measured in.
If you are weighing a replacement against a repair, central AC vs a window unit covers whether whole-house cooling still makes sense for your layout.
Frequently Asked Questions
How long does a central air conditioner last?
15 to 20 years on average (NerdWallet), and 12 to 17 years for a well-maintained unit under normal demand (Bob Vila). In a hot climate where the AC runs most of the year, expect the lower end.
Is it worth replacing a 15-year-old AC?
Often, yes. ENERGY STAR treats 10 years as the point to start planning, so a 15-year-old unit is near the end of its life, likely running 30 to 50% less efficiently than a new one, and one compressor failure away from a forced replacement. If it still cools well and has had no major repairs, you can run it — but do not sink a big repair into it.
How long does a heat pump last?
Roughly 10 to 15 years — a few years less than a cooling-only AC, because a heat pump also runs through the winter, so it logs far more hours. ENERGY STAR uses the same 10-year checkpoint for heat pumps and air conditioners.
What's the 50% rule for AC replacement?
If a repair quote comes to half the price of a new unit or more, replace instead of repairing (NerdWallet). A related rule of thumb: multiply the AC's age by the repair cost, and if it clears $5,000, replace.
Does an air conditioner get less efficient as it ages?
Yes. Wear on the compressor and fan motors, a slowly fouling coil, and any small refrigerant loss all drag the effective efficiency down over time. A 15-plus-year-old unit can use 30 to 50% more electricity for the same cooling than a current model (NerdWallet).
Sources
- NerdWallet — Air Conditioner Replacement Cost — many air conditioners have a lifespan of 15–20 years; if a repair equals half the price of a new unit, replace; newer units run 30–50% more efficiently; new central AC $2,500–$4,500
- Bob Vila — How Long Does an Air Conditioner Last? — a well-made, well-maintained central AC under average demand lasts 12–17 years; lasts decades in a temperate region, far less in the desert Southwest; warning signs — grinding/rattling noises, humidity, excess dust
- ENERGY STAR — When Is It Time to Replace? — consider replacing when your AC or heat pump is more than 10 years old — roughly the midpoint of its life; an ENERGY STAR unit can save up to 20% on heating and cooling costs and uses 8% less energy than a conventional new model; also replace if repairs are frequent and bills are rising
- U.S. EPA — Phaseout of Class II Ozone-Depleting Substances (R-22) — the EPA banned production and import of R-22 on January 1, 2020; existing systems can still be serviced, but only with reclaimed or previously produced R-22, and price and availability may change