The average lifespan of a gas furnace is 15 to 25 years. However, lifespan depends on a number of factors, including when the furnace was built, the materials it is made out of and maintenance.
Older gas furnaces tend to last longer because they have very simple designs and are made out of heavier metals. However, these furnaces are often far less efficient than modern models, and they lose efficiency as they age and their parts degrade.
The materials used in gas furnaces also play a role in life span. Heavier materials tend to break down more slowly than lighter ones, which makes them last longer. However, heavy steel and iron parts are not always as efficient as lighter materials. For example, modern condensing furnaces have plastic pipes, which tend to break down faster than metalbut metal pipes are less efficient as they absorb heat.
Maintenance is a major factor in furnace lifespan. Homeowners can boost lifespan by:
- Regularly cleaning and lubricating blowers
- Cleaning air ducts
- Regularly changing filters
- Replacing faulty thermostats
- Having the furnace inspected every 2 years
Homeowners should replace furnaces that do not distribute heat evenly throughout the home, that break down frequently, that make a lot of noise or that do not work efficiently.