How Long Does a Furnace Last?

Short answerA furnace typically lasts about 15 to 20 years. NAHB's 2007 life-expectancy study lists electric furnaces at 15 years, gas at 18 and oil at 20. ENERGY STAR and the Department of Energy both suggest considering a replacement once a furnace is more than 15 years old, especially with frequent repairs.

What this costs

Our national estimates, not quotes.
Option	Job	Low	High
Replace	Furnace Replacement	$2,950	$8,350

Lifespan by fuel

These are averages for planning, not guarantees. NAHB's 2007 study says its figures are a general guideline only, and that installation quality, maintenance, climate and how hard the item is used all change the result.

Electric furnace: 15 years
Gas furnace: 18 years
Oil furnace: 20 years

15 years is a checkpoint, not an expiration date

ENERGY STAR and the Department of Energy use 15 years as the point to start weighing a replacement. A furnace that passes that age isn't automatically finished. It is the age plus these signs that matters.

Frequent repairs and rising energy bills
Some rooms too hot or too cold
Humidity problems or excessive dust
A noisy heating system

What helps it last

NAHB notes that heating equipment needs regular maintenance to run efficiently. ENERGY STAR recommends a contractor check-up on the heating system every fall and checking the air filter every month.

Furnace Won't Turn On? Safe Checks Before You Call

Common questions

Can a furnace last 30 years?

None of the sources opened for this page give a figure that high for a furnace. NAHB's longest listed average is 20 years, for oil. Some units outlast the average, but plan around 15 to 20.

Is it worth repairing a 20-year-old furnace?

ENERGY STAR's rule of thumb points toward replacement for a furnace over 15 years old with repeat problems or costly repairs. See our repair-or-replace page for the full checklist.