Right off the bat, it is necessary to acknowledge that there is no one specific number when it comes to the life expectancy of a furnace. It all comes down to a series of factors, such as its size, how well it has been maintained, its unique features, and when it was manufactured. Generally speaking though, an average furnace will last between 15 to 30 years, notes Consumer Reports. However, if you are diligent with your maintenance routines and have luck on your side, your furnace might last even longer.
According to A-1 Mechanical, an average electric furnace typically lasts longer than its gas counterparts. This is because of the design and the fact that there is no combustion, which also allows the furnace to remain in good condition for longer. However, if your furnace is over 15 years old, it is a good idea to start thinking of a reliable replacement.