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HVAC Education, Buying Tips, Furnaces

How Long Does A Furnace Last?

While there is no one specific answer to the question “how long does a furnace last?” there are a number of factors that can affect the lifespan of a furnace. Quality manufacturing from a reputable brand and professional installation are good places to start. Measures you can personally take to help extend the life of your furnace include scheduling regular maintenance and inspections by a qualified professional in addition to following the recommended schedule for air filter replacement.

Your personal comfort preferences and local climate can also be factors – depending on how warm or cold you keep your home, how often the system runs, and temperature extremes all can affect the lifespan of the furnace as well. Don’t discount the amount you use your air conditioning as well because in many cases, a furnace is a vital component in a central air conditioning or heat pump system.

Understanding the many factors involved in furnace lifecycles can help you make critical decisions regarding repairing or replacing your furnace. And if your furnace is nearing the end of its lifespan, Carrier offers a number of home furnaces to fit a variety of needs and budgets.

how long does a furnace last


A well-maintained furnace can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend its life even longer. Of course, furnace lifespan can be a bit subjective – how many times you are willing to make repairs and when does a repair cost make it more practical to replace it can vary.

When your furnace is about 15 years old, it’s a good idea to start looking at new equipment to be prepared when it comes time to replace your furnace. You’ll want to learn about the most modern, energy-efficient options out there and get an idea of cost. If energy savings is a priority, you’ll want to learn about the Annual Fuel Utilization Efficiency (AFUE) rating.

furnace lifespan


As we’ve discussed, furnace life expectancy can vary quite a bit. Some of the factors that affect your furnace’s life are out of your control, such as sizing and installation of your furnace which are typically determined by your HVAC contractor. Other factors, such as maintenance and thermostat settings are in your hands. Let’s take a closer look:

Furnace Size

It’s important to have an appropriately sized system for your home.

  • Shorter cycles create more wear and tear on the parts of a furnace, so if the system is larger than necessary, it will turn on and off too quickly.
  • Furnaces that are too small for the space may stay on too long and struggle to heat your home, which can also add wear and tear on parts.

Poor Furnace Installation

Poor installation can affect the lifespan of your furnace for a number of reasons. This is why it’s so important to select a qualified HVAC professional, like your local Carrier expert, to install your system.

  • Poorly designed, sized, or sealed ductwork impacting airflow can affect your comfort and system efficiency
  • Poor drainage system for high efficiency furnaces
  • Incorrectly installed fuel lines

Lack of Routine Maintenance

When you ignore recommended maintenance, dirty buildup on heat exchangers, burners, fan blades can reduce you’re the life of your furnace in a number of ways:

  • Restricted airflow from dirty filters can make the system work harder
  • Imbalanced fans can affect the life of motors
  • Less efficient heat transfer from heat exchangers can make the system work harder

Thermostat Settings

Your personal comfort preferences can affect the life expectancy of your gas furnace. The U.S. Department of energy recommends setting your heating system thermostat at 68° Fahrenheit during the winter for both energy efficiency and adequate comfort.1 Keep in mind that a thermostat set too high or too low can make the system run more frequently, which can reduce its lifespan.


Regardless of how well the furnace is made and how well you maintain it, the day will come when it has reached the end of its usefulness. Here are some warning signs that your furnace may need to be replaced:

  • Frequent service calls
  • Expensive repair bills
  • Uneven temperatures
  • Inability to stay at the thermostat’s temperature setting
  • Furnace blowing cold air
  • New or increased noises
  • Increase in energy bills, especially for highly efficient furnaces


The two easiest ways to extend furnace lifespan are replacing the air filter as recommended by the manufacturer and with annual maintenance from your local HVAC dealer. Dirty, clogged filters can restrict airflow, making the furnace work harder and for longer hours, both of which can affect its lifespan. Dirty buildup on internal components affect performance and – again – make the system work harder and potentially reduce its life. For more details on furnace service, be sure to visit our dedicated page on that subject.

In addition, keeping your home properly insulated and sealed can help by preventing thermal loss and cold air infiltration which can put undue strain on your system. Keeping ductwork clean and properly sealed/repaired can also help extend the life of your furnace. Finally, keeping your thermostat settings at or near the DOE’s recommendations can help with efficiency, which in turn can help extend furnace life.

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