How Long Is a Furnace’s Service Life?

February 2, 2023
Furnace Replacement in Detroit, MI

A furnace is a major investment for a homeowner around Roseville and throughout the Detroit Metro Area. It’s vital for keeping your family safe. No matter what kind of home you have, your furnace has a limited service life and will eventually need a replacement. Let’s consider how long a furnace should last, the factors that will affect its service life, and signs that it may be time to replace your current unit.

Broad Understanding of Service Life

There are a number of factors that will determine how long you can expect your furnace to function, and we’ll dig into some of them here. However, the national average for a natural gas forced-air furnace is 15 to 20 years.

That said, some people enjoy a much longer service life, and others experience a shorter one. Keep in mind that while your furnace may continue heating your home, it will lose its efficiency over time. Furthermore, newer models tend to offer better efficiency than older models did even when they were new. That means that if you have a 12-year-old furnace that’s still operating at peak efficiency, it will be less efficient than a comparable newer model.

Some people take the approach that if it’s not broken, don’t mess with it. Unfortunately, this leaves you at risk of needing an emergency replacement, which is the most stressful and costly way to replace your system.

Furnace Size

Getting the right size of furnace is critically important for both achieving the longest life from your furnace and maintaining your personal comfort. Smaller furnaces are less expensive than larger units. However, going too small will cause your furnace to run long heating cycles, reducing your system’s service life and increasing operating costs while never reaching your ideal temperature.

A unit that’s too large is equally problematic, causing the device to short cycle because of excessive heat buildup in the system. The heat dissipates rather quickly once the system shuts down, and it will then come back on in a perpetual cycle.

Starting the system is the most strenuous part of the heat cycle, causing the most wear on the components. This added wear significantly reduces your unit’s service life and prevents your home from heating effectively.

How You Use the Furnace

Believe it or not, how you use your furnace will also directly affect how long it will serve your home. The greater the difference between the air temperature outside and the temperature you have it set to, the greater the strain is on the system.

The higher you set the temperature on your thermostat, the more fuel you consume, especially on the coldest days. This is why the EPA has recommended maintaining a temperature around 68 degrees Fahrenheit. It just so happens that this temperature also reduces the strain while providing a moderately comfortable environment. A zoned system will allow you to maintain a slightly higher temperature in some areas without drastically impacting the wear on your system.

How Your Unit Is Installed

Having your unit installed properly will have an impact on how soon you need repairs and how long it will last. This is why most furnace manufacturers require professional installation as a term of the factory warranty. If someone installs your furnace but doesn’t understand the testing needed during installation and follow the proper steps, it may not run optimally. The results can range from degraded efficiency to gas leaks and worse. Ultimately, it degrades your unit’s service life.

Your Home’s Insulation

How well your HVAC system works is dependent on several factors all working together. Having a high-efficiency system alone won’t actually result in energy savings. There are three legs of the heating stool: the heating equipment, your home’s insulation, and your ventilation.

The recommended attic and wall insulation in this part of Michigan is R49 and above, which is a minimum of 14 inches of standard fiberglass bat insulation. Less insulation than this results in your heat escaping more quickly, leading to more frequent heating cycles, which will reduce the equipment’s service life.

Routine Maintenance

Professional technicians cannot overstate the importance of routine furnace maintenance, usually conducted in the fall. Your furnace is a mechanical system that requires periodic checks to ensure each component continues operating effectively.

It also requires regular cleaning to prevent airflow restrictions from forming in the system. The common areas that affect your efficiency are your heat exchanger, circulating fan, and ducts. You should have routine maintenance every year to keep your furnace operating at peak efficiency.

Part of what’s included in this maintenance is cleaning and inspecting the heat exchanger, cleaning and balancing the circulating fan, and checking electrical connections. Neglecting maintenance increases the strain on your equipment, compounding every year you fail to get a tune-up. Duct cleaning is not usually included in routine furnace maintenance, but this should be done at least every 3 to 5 years.

We also cannot overstate the importance of your air filter as part of routine furnace maintenance. The kind of filter your furnace uses will determine how often you need to replace it. The common 1- and 2-inch filters may last anywhere from 30 to 90 days, whereas a 6-inch filter may last 6 months or more. Replacing your filter is the one part of furnace maintenance that you, as the homeowner, should undertake.

Your Indoor Air Quality

Your home’s air quality also drastically impacts your system’s performance and service life. More contaminants in the air lead to more contaminants collecting in your system and air ducts, causing airflow restrictions more quickly. Air quality is especially poor in older homes, homes with pets, and homes where someone smokes.

A good gauge of your air quality is how quickly dust collects around your home and how quickly your furnace filter gets dirty. If you find that it’s dirty in under 30 days, you may want an indoor air quality evaluation so you can consider solutions. These can range from whole-home humidifiers to air scrubbers and purifiers to improving your home’s ventilation.

How Frequently You Need Repairs

When one part of your system isn’t working properly it adds strain to all the other parts collectively. This means that ignoring what you think is just an annoying sound may result in major repairs and a shortened service life. If you think there’s a problem with your furnace or another part of your HVAC system, seek repairs quickly to minimize the impact on your system’s service life.

Signs You Need a New Furnace

There are specific signs that may suggest it’s time to plan for a new furnace. We’ve already discussed the factor of age and planning for a replacement when the furnace nears the average life expectancy.

You should also keep an eye on your repair history. Multiply the total cost of your repairs over the past two seasons by the age of your furnace. Once that exceeds the cost of a new unit, it makes more sense to replace it than to continue fixing it. Other signs you need a replacement include the following:

  • Unusual sounds or odors
  • Failure to reach the thermostat setting
  • Uneven heating throughout your space
  • A significant increase in energy consumption

Few companies serving the comfort and safety needs of the Roseville area have the 75 years of trusted service provided by us at C & C Heating & Air Conditioning. Our technicians proudly stand behind our AC and heating installation, maintenance, and repair services along with our indoor air quality solutions and water heater services. Call us today to schedule a consultation to evaluate whether your home needs a new furnace.

company icon