How long do furnaces last?
Most furnaces last 15 to 20 years. A furnace is commonly given 15 to 20 years, and ENERGY STAR suggests considering replacement of an older one for efficiency.
A furnace you ignore tends to fail on the coldest night. A fall check by a technician and a clean filter go a long way, and the carbon monoxide alarm matters as much as the furnace.
Typical lifespan: 15 to 20 years
A furnace is commonly given 15 to 20 years, and ENERGY STAR suggests considering replacement of an older one for efficiency.
Furnace maintenance checklist by season
Spring
Change the filter and note the date. Close any seasonal supply registers only if your installer advises it.
Summer
Schedule the annual inspection before the busy season so you are not waiting on a service call in the first cold snap.
Fall
Test the thermostat and run the furnace for a full cycle. Smells at first startup are usually dust burning off, but a gas smell or a persistent odor is not. Test carbon monoxide alarms and replace their batteries.
Winter
Check the filter monthly during heavy use and replace it when dirty; the Department of Energy says to check at least monthly during the season. Keep vents and the area around the furnace clear, and make sure the outdoor intake and exhaust are free of snow.
Signs your furnace needs replacing
- The furnace is at or beyond about 15 to 20 years old and repairs are frequent.
- Rising heating bills without a change in use.
- Uneven heating, short-cycling, or loud banging, rattling or squealing.
- A yellow or flickering burner flame instead of blue, or soot around the unit. Call a technician.
- A cracked heat exchanger, which a technician must diagnose, or carbon monoxide alarm activations. Leave the home and call emergency services.
Typical furnace warranty
Parts warranties are commonly five years, and are often extended to ten years if the product is registered online within a set window. The heat exchanger often has a longer limited warranty. Labor is usually separate, so check what your installer's labor warranty covers.
An appliance warranty tracker keeps your furnace's coverage dates and receipt in one place.
What to keep for a furnace
- The installation invoice and warranty registration confirmation
- Model and serial number from the label inside the blower door
- Annual service reports
- The filter size and the date of the last change
Common questions
How long do furnaces last?
Most furnaces last 15 to 20 years. A furnace is commonly given 15 to 20 years, and ENERGY STAR suggests considering replacement of an older one for efficiency.
When should I replace my furnace?
Consider replacement when it is past about 15 years and repairs are frequent, or the heat exchanger is cracked. A newer unit may be more efficient, and ENERGY STAR lists certified models.
How often should I change a furnace filter?
Check it monthly in the heating season, and replace it when it is dirty. Many homes need a change every one to three months depending on the filter type and the household.
How do I maintain a furnace?
Follow your manual first. Each season: spring, change the filter and note the date. Close any seasonal supply registers only if your installer advises it. Fall, test the thermostat and run the furnace for a full cycle. Smells at first startup are usually dust burning off, but a gas smell or a persistent odor is not. Test carbon monoxide alarms and replace their batteries.