How Long Does a Furnace Last? Average Life

How long does a furnace last?

Most manufacturers put a furnace’s typical life at 15 to 20 years: Carrier, Lennox and Trane all use that range, and Bryant says 15 to 25. The U.S. Department of Energy estimates the average life of a gas furnace at 21.5 years. ENERGY STAR suggests having heating equipment evaluated once it’s more than 10 years old. The serial number on the rating plate tells you how old yours is.

Why is DOE’s number higher than the manufacturers’?

The Department of Energy’s 21.5 years is a statistical average for gas furnaces in its efficiency analysis, so it’s pulled up by the furnaces that keep running for decades. The 15 to 20 years manufacturers quote is a typical service life. Neither is a promise for any one furnace.

When should a furnace be checked?

ENERGY STAR suggests having heating and cooling equipment evaluated if it’s more than 10 years old or isn’t keeping the house comfortable. That’s a check-up, not a replacement date: a technician can tell you how yours is holding up.

How do I find out how old my furnace is?

Read the rating plate. On most furnaces it’s inside the front panel. Trane and American Standard tell owners to look for an MFG Date on the nameplate. Others code the date into the serial number:

Goodman and Amana: the first four digits are the year and month.
Lennox: the third and fourth digits are the year, and the letter after them is the month.

We’re adding more brands as we confirm each manufacturer’s format from its own documents.

Sources

Carrier, How Long Do HVAC Systems Last?. Carrier’s lifespan table lists 15 to 20 years for furnaces.. Checked October 19, 2026.

Lennox, How Long Does a Furnace Last?. Furnaces typically last 15 to 20 years with proper care.. Checked October 19, 2026.

Trane, How Long Does a Furnace Last?. The average furnace will last 15 to 20 years; look for the MFG Date on the nameplate.. Checked October 19, 2026.

Bryant, How Long Do HVAC Systems Last?. Furnaces (gas, electric or oil) last 15 to 25 years.. Checked October 19, 2026.

U.S. Department of Energy, Energy Conservation Program: Energy Conservation Standards for Consumer Furnaces (final rule, 2023). DOE estimates the average product lifetime to be 21.5 years for non-weatherized and mobile home gas furnaces.. Checked October 19, 2026.

ENERGY STAR (U.S. EPA and DOE), Heat & Cool Efficiently. If your HVAC equipment is more than 10 years old or not keeping your house comfortable, have it evaluated.. Checked October 19, 2026.

Get the home systems age report

We’re building a home systems age report: every major system in your home, each with its age, typical life and replacement budget.

How long do AC units last?

A central air conditioner typically lasts somewhere between 12 and 20 years, depending on whose figure you use: Carrier and Lennox say 15 to 20, while American Standard and Bryant say 12 to 15. Heat pumps run shorter, at 10 to 15 years by Carrier’s, Lennox’s and Bryant’s counts. To see where yours stands, read the build date from the serial number on the outdoor unit.

How long do boilers last?

A home boiler typically lasts 15 years or more, and often much longer. Weil-McLain says many residential boilers give 15 to 20 years of reliable service or longer, U.S. Boiler expects a conventional cast iron boiler to last 20 or more years, and Bryant puts boilers at 15 to 30 years. Condensing boilers sit nearer the low end: U.S. Boiler gives them 15 or more years.

How old is my Goodman or Amana furnace?

On a Goodman or Amana furnace, the first four digits of the 10-digit serial number are the year and month it was built: two digits for the year, then two for the month. Goodman’s furnace warranty gives the example: a serial that starts 2610 was made in October 2026. The rating plate is on the inner wall of the furnace, behind its front panel.

How old is my Lennox furnace?

On a Lennox furnace, the third and fourth digits of the serial number are the year it was built, and the letter after them is the month: A for January through M for December, skipping I. A serial that starts 5921J was built in September 2021 at Lennox’s Marshalltown heating plant. The rating plate is inside the furnace, behind the top front panel, on the left side of the cabinet or on top of the blower deck.