Average Life of a Furnace: Signs It’s Time to Replace & Maintenance Tips

Key Takeaways:

On average, furnace life expectancy is between 15 and 30 years.
The average life of a furnace is largely dependent on its make, model, year of production, and quality of preventive maintenance throughout its life.
Furnace inspections, filter changes, and other maintenance tasks are essential.
Increasing energy bills, strange noises, uneven heating, and increasingly frequent breakdowns are all signs that a furnace could be nearing the end of its life.

You can get a surprising amount of mileage out of your furnace at home, but every appliance needs to be replaced eventually. We’ll share some maintenance tips to help you maximize the lifespan of your furnace and review the signs that suggest you’re finally due for a replacement.

What Is the Average Life Expectancy of a Furnace?

Just how long does a furnace last? The typical range is between 15 and 30 years, though of course there are outliers. A particularly poorly maintained or improperly installed furnace might fail after only 10 years, and one that is meticulously cared for may push 35 or 40 years.

You can get a more precise estimate of your furnace’s predicted lifespan by considering what type of furnace you own and the factors that play into its health. More on this below.

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Does Furnace Lifespan Vary by Type?

Yes, some types of furnaces last longer than others. So how long does a gas furnace last relative to an electric or oil-burning furnace? Generally, furnaces that use gas and oil fail sooner than electric furnaces and boilers. Refer to the table for a more detailed comparison.

Furnace Type	Average Lifespan	Pros	Cons
Gas furnace	15–20 years	Fast and efficient heating Lower fuel costs	Somewhat shorter lifespan Usually more expensive to install
Oil furnace	15–25 years	Powerful and reliable heating	Lower efficiency Higher and more volatile fuel costs
Electric furnace	20–30 years	Long lifespan Inexpensive installation	Higher long-term operating costs
Boiler	15–30 years	Long lifespan High efficiency	Often requires complex maintenance High installation costs

Key Factors That Affect How Long a Furnace Lasts

Many variables can affect a furnace’s longevity beyond its fuel source. Additional factors include the following:

Frequency and quality of maintenance. Furnaces should be professionally serviced every year, typically ahead of the cooling season. Failure to keep up with inspections, cleanings, filter changes, and replacements of worn parts will increase the likelihood of an early breakdown.
Humidity and ventilation. High humidity levels can increase the risk of rust and corrosion, reducing a furnace’s lifespan. Poor ventilation can negatively affect the appliance’s longevity and performance as well, as dust and particulate matter can more readily accumulate on the component parts, impairing efficiency.
Degree and manner of use. Limited wear and tear will help a furnace last longer. This means operating the furnace less often, setting the thermostat at a reasonable level, and avoiding frequent thermostat adjustments that can push the furnace to work harder to bring the home up to temperature.
Climate. Furnace durability can correlate with climate. You’re likely to demand more of your furnace in a colder climate, increasing wear and tear. You can expect a little more mileage out of your heating equipment if you live somewhere with mild winters.
Quality of installation. A substantial percent of HVAC systems across the United States are improperly installed. According to the Department of Energy, flawed installs can result in more than a 30% reduction in efficiency. This can stress the furnace and other HVAC equipment over time.
Efficiency and year of manufacture. Modern high-efficiency furnaces are more likely to last longer than comparable appliances with outdated designs.

Signs Your Furnace Is Nearing the End of Its Life

If your furnace is getting up there in age, be mindful of signs that suggest a breakdown is imminent. Warning signs include:

Inadequate or uneven heating
Higher energy bills
More frequent malfunctions
Unusual noises
Short cycling, or frequently turning on and off
Decreased efficiency
Tripped breakers when the furnace engages

The presence of these symptoms doesn’t guarantee the need for an immediate replacement. You may be able to troubleshoot your furnace to isolate the cause of the problem, then remedy the issue with a quick DIY fix.

How to Extend Your Furnace’s Lifespan With Proper Maintenance

Preventive maintenance is critical to getting as many years as possible out of your furnace. Schedule a professional service checkup for your furnace at least once per year, ideally before the cold weather sets it. You should have your broader HVAC system professionally serviced twice per year.

A thorough checkup may involve the following tasks:

Testing for carbon monoxide and particulate matter
Ensuring the furnace vent is unobstructed and adequately channeling byproducts of combustion out of the home
Checking the burners, ignition systems, and flame sensor
Cleaning or replacing the air filter
Inspecting the heat exchanger for cracks or other kinds of damage
Calibrating the thermostat
Confirming the functionality of all mechanical parts, such as the blower fan
Testing the furnace transformer and other electrical components
Assessing for safety hazards, such as a faulty limit switch

A thorough maintenance checklist serves two important purposes: it keeps your equipment in good condition so it functions optimally, and it helps you identify potential problems early on so that you can resolve them before they get out of hand.

Furnace Warranty Coverage

Even with exceptional maintenance, all appliances need to be replaced eventually. If and when your furnace does break down, you can protect yourself from out-of-pocket costs by leveraging your home warranty coverage. Liberty Home Guard’s comprehensive systems coverage can support your furnace and broader HVAC system. Find your plan by calling (833)-545-3434.

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Frequently Asked Questions

How long does a heater last?
A major home heating appliance will usually last a minimum of 15 years. If you keep up with maintenance and the conditions are favorable, a heater or furnace could last for 30 years or more
Do gas furnaces last longer than electric ones?
No, gas furnaces do not usually last longer than electric furnaces. At the high end, gas furnaces may last 20 or 25 years, but electric furnaces may keep working for 30 years or more.
Of course, more plays into the longevity of an appliance than just its fuel source. A well-maintained gas furnace will likely outlast a neglected electric one.
What habits help extend a furnace's lifespan?
Some simple practices can help you boost your furnace’s longevity. Replace the air filter every 1 to 3 months and have your furnace professionally serviced at least once per year. Keep the thermostat setting mostly steady so the furnace doesn’t need to work too hard to bring the home up to your desired temperature. Take steps to make your home more energy efficient to limit heat loss and reduce demand on your furnace.
What are the warning signs that a furnace needs replacing?
Signs that suggest your furnace is at the end of its life include poor heating, strange noises, and increasingly frequent malfunctions and breakdowns. Also keep an eye out for rising energy bills, which suggest decreasing furnace efficiency.
Electrical problems, such as tripped breakers, could suggest that the furnace sequencer or other components are failing, and it might be worth investing in a new appliance instead of simply replacing component parts.
Is it cheaper to keep repairing an old furnace or replace it?
When deciding between repairing and replacing your furnace, consider the cost of repair, the age of the furnace, and the likelihood of additional repairs in the near future. If your furnace is within a few years of its average life expectancy, a replacement may be the better choice.
How does climate affect furnace longevity?
You’re more likely to work a furnace longer and harder in colder climates, so a furnace’s lifespan might average a little longer in places with milder winters. Humidity can also play a role, as humid environments can facilitate corrosion.