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The Average Lifespan of a Gas Furnace

temperature rising image by Keith Frith from

Natural gas furnaces are a common way of heating modern homes. They are relatively inexpensive to maintain; an annual inspection should cost between $50 and $100. And be sure to have a working carbon monoxide detector in your home, especially if your furnace is over 15 years old.


The average gas furnace will last about 20 years before needing to be replaced. If yours is over 15 years old consider having it replaced earlier than that. By doing this, you will avoid the chance of it breaking down in the middle of winter.

Extending Furnace Lifespan

You can help your gas furnace last longer by doing regular maintenance. Check the chimney and vent connector, oil the pumps, blowers and motors if necessary, and clean the blower blades. Also replace the filter monthly when your heat or air conditioning is on.


Have a professional look at your furnace if it is not working properly. Signs of problems include eye irritation while in the home, soot or carbon deposits in the burner, dust on the burner or a yellow rather than a blue flame.

Lifespan Of A Gas Furnace Ignitor

The ignitor is an important part of a gas furnace. Gas furnace ignitors have a shorter lifespan than some other parts of a gas furnace system. How long your gas furnace ignitor lasts depends partially on how well you maintain your furnace. You must change your filter at least once every 90 days and have a service technician perform routine maintenance on your gas furnace at least once a year. If you don't perform these two steps, the ignitor may not last as long, and the entire furnace can break down, requiring you to replace it prematurely. Some older ignitors have shorter lifespans because they stay on for a longer period of time when you light the furnace. This puts extra wear and tear on the ignitor and makes it more likely that you will have to replace it sooner. This is called delayed ignition, and it can be dangerous -- while the furnace is waiting for the ignitor to spark, gas builds up and can cause an explosion once the ignitor lights.

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