---
title: "How Long Does a Furnace Last? Average Life | What Year Is"
description: "Manufacturers put a typical furnace life at 15 to 20 years, and DOE’s average for gas furnaces is 21.5 years. Here’s how to tell how old yours is."
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last_updated: "2026-10-19"
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# 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.

By [the What Year Is team](https://whatyearis.com/editorial) · Updated October 19, 2026

## 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](https://whatyearis.com/goodman-furnace): the first four digits are the year and month.
- [Lennox](https://whatyearis.com/lennox-furnace): 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

- [How Long Do HVAC Systems Last?](https://www.carrier.com/us/en/residential/hvac-resources/how-long-do-hvac-systems-last/), Carrier. Carrier’s lifespan table lists 15 to 20 years for furnaces.. Checked October 19, 2026.
- [How Long Does a Furnace Last?](https://www.lennox.com/residential/lennox-life/consumer/how-long-does-a-furnace-last), Lennox. Furnaces typically last 15 to 20 years with proper care.. Checked October 19, 2026.
- [How Long Does a Furnace Last?](https://www.trane.com/residential/en/resources/blog/how-long-does-a-furnace-last/), Trane. The average furnace will last 15 to 20 years; look for the MFG Date on the nameplate.. Checked October 19, 2026.
- [How Long Do HVAC Systems Last?](https://www.bryant.com/en/us/products/how-long-do-hvac-systems-last/), Bryant. Furnaces (gas, electric or oil) last 15 to 25 years.. Checked October 19, 2026.
- [Energy Conservation Program: Energy Conservation Standards for Consumer Furnaces (final rule, 2023)](https://www.energy.gov/sites/default/files/2023-09/consumer-furnace-fr.pdf), U.S. Department of Energy. DOE estimates the average product lifetime to be 21.5 years for non-weatherized and mobile home gas furnaces.. Checked October 19, 2026.
- [Heat & Cool Efficiently](https://www.energystar.gov/saveathome/heating-cooling), ENERGY STAR (U.S. EPA and DOE). If your HVAC equipment is more than 10 years old or not keeping your house comfortable, have it evaluated.. Checked October 19, 2026.

## Related pages

- [How old is my Goodman or Amana furnace?](https://whatyearis.com/goodman-furnace): The first four digits of a Goodman or Amana furnace serial number are the year and month it was built. Where the furnace label is, and how to read it.
- [How old is my Lennox furnace?](https://whatyearis.com/lennox-furnace): Find the year and month your Lennox furnace was built from its serial number, where the label sits inside the cabinet, and how to read its model number.
- [How old is my Goodman or Amana furnace?](https://whatyearis.com/goodman-furnace): The first four digits of a Goodman or Amana furnace serial number are the year and month it was built. Where the furnace label is, and how to read it.
- [How old is my Lennox furnace?](https://whatyearis.com/lennox-furnace): Find the year and month your Lennox furnace was built from its serial number, where the label sits inside the cabinet, and how to read its model number.
- [How long do AC units last?](https://whatyearis.com/how-long-do-ac-units-last): Manufacturers put central air conditioners at 12 to 20 years and heat pumps at 10 to 15. Here’s what DOE’s averages say and how to tell how old yours is.
- [How long do boilers last?](https://whatyearis.com/how-long-do-boilers-last): Manufacturers put a home boiler’s typical life at 15 to 30 years, with cast iron at the long end. Here’s what the sources say and how to date yours.

## About this document

This is the Markdown version of a page on What Year Is (https://whatyearis.com). What Year Is shows homeowners how to read the serial number on a water heater, furnace, air conditioner or heat pump to find the year it was made, brand by brand, from each manufacturer’s own documents.

- Site index for AI assistants: https://whatyearis.com/llms.txt
- About What Year Is: https://whatyearis.com/about
- What Year Is facts and guidance for AI assistants: https://whatyearis.com/facts
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