Guides · Equipment

How long does an AC unit last, and how to tell how old yours is

A central air conditioner usually lasts 7 to 15 years. A heat pump, which heats as well as cools, lasts about 10 to 15, and a window unit 5 to 7. The data plate on the outdoor unit tells you how old yours is, and the age decides whether a repair is worth it.

Updated October 31, 20266 min read

How long cooling equipment lasts

Type	Typical life	What usually ends it
Central air conditioner	7 to 15 years	The compressor in the outdoor unit, or a refrigerant leak in an old coil.
Heat pump	10 to 15 years	It runs in winter too, so the compressor works more hours each year.
Outdoor condenser unit alone	8 to 20 years	Coastal salt air and dirt packed in the fins shorten it.
Window air conditioner	5 to 7 years	Sealed units are rarely worth repairing.

Ranges from the InterNACHI standard estimated life expectancy chart. Units in hot climates that run most of the year sit at the low end; well kept units in mild climates at the top.

How to find the age of your AC unit

Go to the outdoor unit and find the data plate, a metal or foil label on the side or back with the model and serial number. Many newer plates print the manufacture date. If yours does not, the date is coded in the serial number. The same brands make furnaces and air conditioners and use the same serial codes:

Carrier, Bryant, Payne and Day and Night: the first four digits are the week, then the year. A serial starting 2214 was made in week 22 of 2014.
Trane and American Standard (since 2010): the first two digits are the year and the next two the week, so 1531 is week 31 of 2015.
Goodman, Amana and Janitrol (ten character serials): the first two digits are the year and the next two the month. 1806 means June 2018.
Lennox, Armstrong Air and Ducane: the third and fourth digits are the year. 5811 means 2011.
Rheem and Ruud: Rheem’s how old is my equipment page decodes the serial.
Any brand: photograph the data plate and the Housemap label scan reads the brand, model and serial, works out the age when the date is printed or the brand’s code is known, and checks for recalls.

The indoor coil and the outdoor unit can be different ages if one was replaced. Read both plates.

Signs an air conditioner is near the end

It is past 10 to 12 years old and needs a compressor or a new coil.
It needs refrigerant topped up every summer, which means a leak.
Warm air from the vents, rooms that never cool, or long run times on mild days.
Higher electric bills in summer with the same thermostat setting.
Loud grinding, buzzing or squealing from the outdoor unit, or a breaker that keeps tripping.
Water or ice around the indoor unit, or ice on the copper line outside in July.
An older system that uses R-22 refrigerant. R-22 is no longer produced in the United States, so recharging one gets harder every year.

Repair or replace

A unit under about eight years old with a failed capacitor, contactor or fan motor is a repair; those parts are small and common. A unit past twelve with a failed compressor or a leaking coil is usually a replacement, because the part is a large share of a new system and the rest of the unit is near the end too.

If the furnace is old as well, replacing both together lets the installer match the blower and the coil, which matters for efficiency. Spring and fall are the slow seasons for installers, and a replacement planned then comes with time to compare quotes.

How to make an air conditioner last longer

Check the filter every month in cooling season and change it when it looks grey. A clogged filter starves the coil of air; see how often to change a furnace filter, since the same filter serves both.
Have the system checked every spring before the heat, as ENERGY STAR recommends: refrigerant charge, electrical connections, coil and condensate drain.
Keep two feet of clear space around the outdoor unit. Cut back shrubs and keep leaves, grass clippings and snow drifts off it.
Rinse the outdoor fins gently with a garden hose in spring, with the power off at the disconnect.
Keep the condensate drain line clear so water does not back up and shut the system off or leak into the ceiling.
Avoid very low thermostat settings on hot days; the unit runs no faster, only longer.

Keep the dates

Write down the install year, the model and serial of both the outdoor unit and the indoor coil, the refrigerant type and each service date. Housemap keeps them on the AC card in your house file, next to the furnace, and sends a reminder before the spring service and each filter change.

Questions

How long does an AC unit last?

A central air conditioner lasts about 7 to 15 years, a heat pump about 10 to 15 and a window unit about 5 to 7. Yearly service and clean filters keep a unit toward the top of the range.

How do I tell how old my air conditioner is?

Read the data plate on the outdoor unit. Many plates print the date. Otherwise it is in the serial number: week then year for Carrier and Bryant, year then week for Trane since 2010, year then month for Goodman, and the third and fourth digits for Lennox.

Is it worth repairing a 15 year old AC?

A small repair such as a capacitor or fan motor can be. A compressor or coil replacement on a 15 year old system usually is not, because the rest of the system is near the end of its life.

What is the most common reason an AC unit fails early?

Dirty filters and coils that make the compressor work harder, refrigerant leaks left unrepaired, and electrical parts that wear out without a yearly check.

Sources

Scan the plate. Know the age.

Photograph the AC data plate and Housemap reads the brand, model and serial, works out the age, checks for recalls and reminds you before the spring service.

Start your house file