How long does a central air conditioner last?

How long a central air conditioner lasts depends on the source you read. Each source measures something different. The U.S. Department of Energy (DOE) modeled average lifetimes for a 2017 efficiency rule. An industry trade group gives a general range on a web page with no date. ENERGY STAR and DOE use an age of 10 years as a prompt to consider replacing a system. We found no government or standards-body field survey that measured how long central ACs last in U.S. homes. This guide compares the sources and explains how DOE got its figures. It also covers the upkeep that ENERGY STAR ties to equipment life.

What each AC lifespan figure measures

Source	What it says	What kind of figure it is
U.S. Department of Energy (2017)	National average lifetime of 21.2 years for central ACs and 15.3 years for heat pumps	Modeled average from a 2017 efficiency rule
Air-Conditioning, Heating, and Refrigeration Institute (AHRI), the industry's trade group	Central AC "12- to 15- years if it is properly installed and maintained"; heat pumps "about 14 years"	General advice on an undated page that also cites an outdated efficiency minimum
ENERGY STAR	"Your heat pump or air conditioner is more than 10 years old."	A reason to consider replacement
DOE Energy Saver Guide (2022)	"Your heat pump or air conditioner is more than 10 years old."	Listed among reasons to consider replacing a heating system

None of these sources describes a field measurement of AC life in homes. DOE's figures come from a model it used to set efficiency standards.

DOE's modeled AC lifetimes by region (2017)

DOE published a direct final rule on January 6, 2017. In it, DOE estimated the average lifetime "to be 21 years for central air conditioners and 15 years for heat pumps." The rule's Table IV-16 gives the figures to one decimal place and splits them by region. DOE says it developed separate lifetime distributions for three regions: North, hot-humid and hot-dry. The table also lists a national average.

A footnote in the rule's text version names the places in the hot-humid region. The list reads: "Alabama, Arkansas, Delaware, Florida, Georgia, Hawaii, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, Puerto Rico, South Carolina, Tennessee, Texas, Virginia, the District of Columbia, and the U.S. territories." Another footnote says, "Hot-Dry includes the states of Arizona, California, Nevada, and New Mexico." The parts of the rule we reviewed do not list the states in the North region.

DOE's shipments model assumes that when new products cost more, some consumers will choose to repair failed units instead of replacing them. It estimates that a repaired unit lasts some extra years, which DOE calls an extended lifetime. On average, that extra time is about half of the original lifetime. After that, the repaired unit triggers a new replacement shipment.

How DOE turned operating hours into years

The rule explains how DOE turned run time into years. It says that within each region, the scale parameter is adjusted to reflect differences in average yearly operating hours. The rule then makes a general point about mechanical devices. It says equipment life is defined as total lifetime operating hours. DOE says you can turn that figure into a service lifetime in years by dividing it by the average yearly operating hours. The rule concludes that equipment run for fewer hours "can therefore be expected to have a longer service lifetime."

DOE did not link failure to run time alone. The rule says it is likely that some aspects of product failure depend on the equipment's actual age. So DOE assumed that half the time, failure would be tied to lifetime operating hours. It assumed that the other half of the time, failure would be tied to product age. DOE says this approach produced the regional figures in Table IV-16.

The parts of the rule we reviewed do not name heat, humidity or salt air as reasons the regional figures differ. We do not suggest a cause either.

AHRI's 12-to-15-year range comes from an older page

DOE's rule describes AHRI as a trade association within the global industry. It says AHRI represents makers of heating, ventilation, air conditioning and refrigeration (HVACR) and water heating equipment. AHRI's consumer page says, "The average life span of central air-conditioning system is 12- to 15- years if it is properly installed and maintained." It adds, "Heat pumps have about the same life-span — about 14 years — when recommended maintenance is followed." It also says, "Newer units manufactured in recent years are expected to last even longer."

The page has no date. It does not say which years count as recent. It also still says systems "manufactured today must have a seasonal energy efficiency ratio (SEER) of 13 or higher." Under 10 CFR 430.32, central ACs and heat pumps made on or after January 1, 2023 are rated in SEER2. We treat the AHRI page as general industry advice, not a study. AHRI's range is lower than DOE's modeled national average. The two sources use different methods. Our SEER2 guide covers today's federal minimums.

The 10-year mark is a replacement prompt, not a lifespan

ENERGY STAR has a page called When is it time to replace? It lists reasons it may be time to call a professional contractor about a change. One of them is "Your heat pump or air conditioner is more than 10 years old." DOE's 2022 Energy Saver Guide uses the same line. There, it is one of the reasons to consider replacing a heating system.

The same ENERGY STAR page suggests a replacement that has earned the ENERGY STAR label. That advice no longer fits central ACs. ENERGY STAR's sunset notice says, "On February 1, 2026, EPA sunset the ENERGY STAR specification for central air conditioners."

Maintenance that affects how long an AC lasts

ENERGY STAR's maintenance checklist says these problems can damage your equipment or shorten its life:

• Dirty coils. Dirty coils make it harder for the system to cool your home. They make it run longer, which raises energy costs and shortens the equipment's life.
• Wrong refrigerant charge. Too much or too little refrigerant makes your system less efficient. This raises energy costs and shortens the equipment's life.
• Faulty electrical connections. These can make your system run unsafely and shorten the life of major parts.
• Dirty filters. ENERGY STAR says to inspect, clean or change the air filters in your central air conditioner, furnace and/or heat pump once a month. It warns, "A dirty filter can increase energy costs and damage your equipment, leading to early failure."

The checklist also warns that "Airflow problems can reduce your system's efficiency by up to 15 percent." It says a plugged condensate drain "can cause water damage in the house and affect indoor humidity levels." ENERGY STAR recommends "having a contractor do annual pre-season check-ups." It says "it's best to check the cooling system in the spring and the heating system in the fall."

Oversized equipment and short-cycling

Pacific Northwest National Laboratory publishes the Building America Solution Center (BASC) for DOE. Its 2018 whole-house dehumidification guide says, "Oversizing the cooling system can cause short-cycling of the equipment..." The guide says short-cycling means short periods of "on" time with cooling, followed by long periods of "off" time with no cooling. BASC's 2021 gas-fired boiler guide makes a general point about oversized equipment. It says such equipment can “short cycle,” or turn on and off repeatedly before the demand is met. It adds that this "can have negative impacts on energy use, comfort, and equipment durability." Neither guide gives a lifespan figure for an oversized AC.

AC lifespan in Arizona, Texas and Florida

Our state guides answer the same question with local sources. Arizona is in DOE's hot-dry region. Our guide covers how long an AC lasts in Arizona. Texas and Florida are both in DOE's hot-humid region. See how long an AC lasts in Texas and how long an AC lasts in Florida. If your system cools but the house still feels damp, our indoor humidity guide covers the federal guidance.