Home Help Guides

Mar 10, 2025 | Michael Jestadt

How Long do Furnaces Last?

Like every household item in our home, the heating system also doesn’t last forever. But you can extend its lifespan by following some practices. One common question among homeowners is how long furnaces last. We cannot exactly answer this complicated question because many factors contribute to the lifespan of the furnace system. In this article, we will discuss some ways to extend the life of the furnace system. Let’s get started!

Factors That Affect Your Furnace Life

The following are the key factors that affect the longevity of the furnace system:

Size of the Furnace System

It is important to have the right-sized furnace for your home. If the furnace is too big, it will turn on and off too often, which causes more wear and tear on its parts. If the system is too small, it will run for a long time and struggle to heat your home, which can also damage the parts over time.

Poor Furnace Installation

Poor installation can affect the efficiency of your furnace in several ways, so it’s important to hire an HVAC professional to do the job. Poorly designed or sealed ductwork can reduce airflow, making your system less efficient and less comfortable. High-efficiency furnaces also need proper drainage and fuel lines to be installed correctly to avoid problems.

Thermostat Settings

Your preferences can impact how long your gas furnace lasts. The U.S. Department of Energy suggests setting your thermostat to 68°F in winter for a comfortable, energy-efficient home. If the thermostat is set too high or too low, the furnace may run too often, reducing lifespan.

The Age of Your Furnace

A furnace typically lasts between 15 and 30 years. However, it is advisable to replace it after 15 years. The lifespan of a furnace also depends on the type of fuel it uses. Many homeowners choose to replace an old gas furnace with a new electric one because electric furnaces can last 20 to 30 years. While gas furnaces don’t last as long, they are cheaper and can heat your home faster than electric ones.

Producing Noises

If your furnace makes strange noises, it might be time for a repair or replacement. Sounds like rattling, popping, humming, or screeching can indicate that your furnace is worn out and needs a new one. To lower your energy bills, consider switching to a different heating system, like a boiler, heat pump, or ductless mini-split.

Lack of Routine Maintenance

Skipping annual maintenance can cause dirt buildup on key parts like heat exchangers, burners, and fan blades. This leads to restricted airflow, motor strain from unbalanced fans, and reduced heat transfer, all of which make your furnace work harder and decrease the lifespan of your furnace system.

Temperature Fluctuations

If the temperature is different in each room, it may indicate that you should reach an HVAC expert. Major temperature changes also mean you should start looking for a new furnace. After about 15 years, an old furnace becomes less efficient and struggles to heat your home evenly.

Soot Near Furnace Register

Soot, dust, and air can damage couches, chairs, flooring, walls, and ceilings. If your home has a lot of dust and soot, your furnace system will produce large amounts of carbon dioxide. Soot builds up near the furnace register4, which controls the airflow. If you notice dirt or soot near it, it’s a sign you should call a professional to replace your furnace.

High Energy Bills

As your furnace ages, it may use more energy because of wear and tear or failing parts. Suppose your energy bills are increasing without any sudden temperature drop or rise. In that case, it’s a good time to check your furnace. Replacing a part can help you get lower bills, but if your furnace is over 15 years old, getting a new one will be more efficient and save your money on repairs and energy bills.

Yellow Flames

A furnace in good working condition indicates a clear blue flame. The flame color can change if there is a gas leak or system issues. Homeowners can check the furnace flame through the cover vents while running. If the flame is yellow, the heat exchanger or burner may need cleaning, and it could lead to serious issues like carbon monoxide or gas leaks. A yellow flame is a warning sign and should be checked by a licensed professional immediately.

Factors to Consider to Extend the Life of the Furnace

• Regular Maintenance: Professional maintenance once every year is important to extend the furnace’s lifespan. During annual maintenance, experts ensure all the parts are in working condition. A properly maintained system can outweigh the performance and longevity of the system that is not.
• Clean Filters Frequently: Clean filters help your furnace work better. During winter, your furnace runs more often; change the filters monthly. Dirty filters block airflow, which can cause overheating and damage important parts.
• Quality of the Equipment: The system’s longevity and efficiency depend on the equipment’s quality. Your local HVAC contractor can help you choose the best quality equipment available.
• Usage: If you use your furnace system more frequently due to harsh climates, it needs maintenance more frequently to slow down the effects of usage.
• Moisture and Humidity: Depending on the location, we often feel the effects of humidity. High humidity can cause a furnace to rust over time. To prevent this, control the moisture levels in your home to keep your furnace in good condition.

Schedule a Furnace Service Today

Regular furnace system maintenance prevents sudden breakdown and increases efficiency and longevity. We are here for you if you are unsure whether to repair or replace your furnace system! At Smart Heating and Air Conditioning, we have experts to ensure your home stays warm, safe, and efficient all season long. Contact us today to schedule a Furnace tune-up service and keep your heating system running at its best!