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How Long Does A Furnace Last

Major HVAC manufacturers like Carrier spend a lot of time testing and improving their natural gas furnaces in hopes of delivering a reliable product that keeps their customers warm and cozy for years to come. The question is, how many years can you reasonably expect a furnace to continue delivering warm air? Between 15 and 20 years? 30 years? 40 years? So the answer to the question “how long does a furnace last?” is complicated. Furnace life expectancy, like any other product, will vary greatly for a number of reasons. Installation quality and proper sizing, personal comfort preferences and thermostat settings, climate, quality of your heating fuel source, and regular furnace maintenance all can play a role in either extending... or reducing furnace lifespan. Without putting an actual number on it, your furnace can last as long as you continue to keep up with routine, annual maintenance and minor repairs. And when a major issue presents itself, the decision to repair or replace your furnace with a new one will go a long way towards determining the actual lifespan of your current model.

The average furnace lifespan

Opinions about furnace life expectancy will vary from individual to individual. Much like your car, it’s not uncommon for an older furnace to need some basic repairs. One homeowner might want a new model the first time a minor repair is needed and the furnace is out of warranty. Another might be willing to make a number of repairs before deciding the old furnace is finished. Others might even be willing to replace major components like a heat exchanger or blower motor. But basing your expectation on a furnace’s warranty might be a good place to start. Carrier® furnaces offer a standard, 10-year parts limited warranty.

Factors that Reduce the life expectancy of a furnace

There are a number of reasons why a perfectly well-made furnace might fall short of its expected lifespan. Incorrect sizing, poor quality installation, and lack of routine maintenance are some of the biggest factors. Thermostat settings and external physical factors like high humidity can reduce average life expectancy as well.

Incorrect furnace sizing

Furnaces are available in different “sizes” based on their capacity to produce heat (Btu/h). An incorrectly sized furnace, installed as part of a heating and air conditioning system, will affect the comfort and energy efficiency of your home, and potentially reduce the lifespan of the furnace. Here’s how: because an oversized furnace actually delivers too much heat for the home, it will start up, quickly heat your home to the setting on your thermostat, and turn off. Because the heating cycles are shorter, it takes more of them to keep your home at a consistent temperature. An oversized furnace will create much more wear and tear on components like the blower motor because it cycles on and off much more frequently than a properly sized furnace. An undersized furnace will struggle to keep your home warm, will run for longer periods of time, and potentially shorten the life of your furnace as well.

Poor quality installation

A lot of contractors can install a furnace, but not all contractors install furnaces well. Poorly designed, sized and sealed ductwork can restrict airflow or reduce comfort and efficiency. High efficiency furnaces actually create condensation during normal operation and include a condensate drain. If the drain system is poorly designed and backs up, it can cause problems with furnace performance and reliability. Other issues such as incorrectly installed venting and fuel lines can affect performance as well, and it all can add up to reduced furnace lifespan.

Lack of routine maintenance

As you would expect, regular, routine maintenance is recommended to extend the performance and lifespan of your furnace. Most homeowners can inspect and clean or replace an air filter. But an HVAC professional will dig deeper with regular clean and check appointments. They can clean and inspect internal components like the heat exchanger, blower and motor assembly, inducer motor, burner and gas valve, and condensate traps and drains. And, they can make adjustments or minor repairs to improve performance and avoid bigger issues down the road.

Thermostat settings

Everybody has their own idea about how to set the thermostat. Some like to dial down the temperature and live with a cooler home for higher energy efficiency heating. Others want to crank up the heat for greater comfort. However, if you set your thermostat too low or too high you can potentially damage components that may either shorten the life of the furnace or lead to an inconvenient or expensive service call. It is generally recommended to set the thermostat no lower than 60⁰ Fahrenheit and no higher than 80⁰ Fahrenheit.

Signs You Are Nearing the End of Your Furnace Life Expectancy

While most homeowners would like their furnace lifespan to be forever, every unit will eventually need to be replaced. And, most of the time there will be signs that an aging furnace is ready to call it quits. Frequent service calls and expensive repair bills are obvious indications that it may be time to replace your furnace. Performance issues such as a general lack of comfort, furnace blowing cold air, uneven temperatures around the house, new/increased noise and trouble keeping up with the thermostat’s temperature setting all may indicate a serious issue and potentially the end of the furnace’s useful lifetime. Less obviously, if you notice an increase in your energy bills every month, you may have an issue with your heating system that needs attention.

How to extend the furnace lifespan

Most HVAC manufacturers and service technicians would probably agree that the number one way to extend furnace life expectancy is routine cleaning, maintenance and service. Keeping filters, motors and the heat exchanger free from dirt, dust and other debris will help ensure the best performance and efficiency of your furnace and can help prevent premature failure. For more detailed information on furnace service, what to expect, and how it can affect HVAC system performance, visit our dedicated page on this topic. Checking and cleaning a furnace air filter is usually a simple DIY project that most homeowners can handle themselves and offers a side benefit of maintaining better indoor air quality. Finally, if you do decide to replace your current system, you might consider including a heat pump with your new furnace instead of an air conditioner to create a dual-fuel system, which could lessen the workload of the furnace. Regardless, be sure to hire a qualified HVAC contractor to be sure the new furnace is sized and installed properly.

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