How long does a central air conditioner last?
Published figures for a central air conditioner run from 10 to 21 years. The home builders’ survey gives 10 to 15 years, and the US Department of Energy’s analysis uses an average of about 21. Climate explains much of the gap: a unit in a hot region runs many more hours each year.
What the published figures say
| Years | Source | What the figure is |
|---|---|---|
| 10 to 15 | NAHB and Bank of America Home Equity, Study of Life Expectancy of Home Components (2007) | From the study’s heating and cooling table. Its appliance table gives 15. |
| 15 to 20 | US Department of Energy, Building America Solution Center, air conditioning guide | A general statement about heating and cooling equipment. |
| About 21 | US Department of Energy, energy conservation standards for central air conditioners and heat pumps, final rule (2017) | Average lifetime in the Department’s cost analysis, built from household survey data. |
| 18 in the hot and humid Southeast, 24 to 25 elsewhere | US Department of Energy, Federal Energy Management Program, purchasing energy-efficient residential central air conditioners | Assumptions used to compute lifetime energy cost. |
| More than 10: consider replacing | ENERGY STAR, when is it time to replace heating and cooling equipment? | A prompt to weigh replacement, not a life expectancy. |
The sources measure different things, which is why they differ. A survey of first owners gives a shorter figure than an analysis that follows units until they are scrapped. All of them describe typical equipment. A given unit can fail sooner or run far longer, and age alone is not a reason to replace anything that works safely.
How old is yours?
The build date is coded into the serial number. Where to find it: How old is my AC unit or heat pump?
Find the age from the serial number
What the build year tells you
- Built before 2010, when new units stopped being charged with R-22 at the factory. Many units of this age use R-22, which has not been produced or imported since 2020. The rating plate names the refrigerant.
- Most units of these years use R-410A. Since January 1, 2025 new systems are built for refrigerants with a lower global warming potential, such as R-454B and R-32. Servicing R-410A systems is still allowed.
- Built after the refrigerant rules changed on January 1, 2025. New systems use R-454B or R-32, which are mildly flammable. Replacement outdoor units for existing R-410A systems are still made, so check the refrigerant named on the rating plate.
- Built before January 23, 2006, when the federal minimum efficiency rose from 10 SEER to 13 SEER.
- Built under the SEER2 ratings that took effect on January 1, 2023. SEER2 numbers come from a different test and cannot be compared directly with older SEER labels.
What shortens or extends its life
- Long cooling seasons. More running hours each year wear the compressor sooner.
- Dirty coils and filters, which make the compressor work against higher pressure.
- A refrigerant leak that is topped up again and again without being repaired.
- An oversized unit, which starts and stops many times an hour.
- Maintenance that is skipped. A yearly check finds a failing part before it damages others.
Signs that replacement is near
- A failed compressor that is out of warranty. The repair often costs a large share of a new outdoor unit.
- A refrigerant leak in a unit that uses R-22. R-22 has not been produced or imported since 2020.
- Higher electricity use for the same weather.
- A house that feels damp while the air conditioner runs.
- Repairs that are becoming frequent.
Sizing the replacement
Sources
- NAHB and Bank of America Home Equity, Study of Life Expectancy of Home Components (2007): https://teamcomplete.com/wp-content/uploads/2015/12/07-NAHB-Life-Expectancy-Depreciation-Feb-2007.pdf
- US Department of Energy, Building America Solution Center, air conditioning guide: https://basc.pnnl.gov/resource-guides/air-conditioning
- US Department of Energy, energy conservation standards for central air conditioners and heat pumps, final rule (2017): https://www.govinfo.gov/content/pkg/FR-2017-01-06/html/2016-29992.htm
- US Department of Energy, Federal Energy Management Program, purchasing energy-efficient residential central air conditioners: https://www.energy.gov/cmei/femp/purchasing-energy-efficient-residential-central-air-conditioners
- ENERGY STAR, when is it time to replace heating and cooling equipment?: https://www.energystar.gov/saveathome/heating-cooling/replace
- Code of Federal Regulations, 40 CFR 82.15 and 82.16, limits on R-22 (HCFC-22): https://www.ecfr.gov/current/title-40/section-82.15
- US Environmental Protection Agency, Technology Transitions sector tables for air conditioning and heat pumps: https://www.epa.gov/climate-hfcs-reduction/sector-tables
- Code of Federal Regulations, 10 CFR 430.32, energy and water conservation standards: https://www.ecfr.gov/current/title-10/section-430.32
Other equipment
- How long does a water heater last?
- How long does a tankless water heater last?
- How long does a furnace last?
- How long does a heat pump last?
- How long does a refrigerator last?
- How long does a washing machine last?
- How long does a clothes dryer last?
- How long does a dishwasher last?
- How long does a range or oven last?
Figures last checked against their sources on October 5, 2026. Method and sources.