The ignitor is an important part of a gas furnace. When you turn the furnace on, the ignitor produces a spark that hits the gas, causing the furnace to light. If the ignitor doesn't work properly, your furnace might not light at all or may produce insufficient heat to your home. Ignitors typically last four to seven years although they may wear out sooner if you don't maintain them.
Gas furnace ignitors have a shorter lifespan than some other parts of a gas furnace system. According to the Gas Furnace Guide, ignitors have an average lifespan of four to seven years. So, after about seven years, you may have to replace the ignitor; however, you probably won't have to replace the entire furnace because other parts, such as the heat exchanger, can last more than 15 years.
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.
Length of Use
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. Newer furnaces have more efficient ignition systems that turn off the ignitor soon after it lights the furnace, thus extending its lifespan.
Symptoms of Ignitor Failure
If the furnace won't light or stay lit, you may have a problem with the ignitor. You also may have ignitor problems if you hear clicking noises coming from your furnace and the furnace takes a long time to light. 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.