The typical lifespan of a furnace is 15-20 years. In fact, many major manufacturers guarantee their furnace’s heat exchangers for 20 years! Typically, your furnace should be replaced every other time your air conditioning is replaced. 

• Some signs that your furnace needs to be replaced include:

• Rust buildup inside furnace cabinet

• Furnace is no longer able to keep up with heating demand

• Furnace is 20+ years old