When should an Armstrong furnace be replaced?

With a 10-year warranty on parts, an Armstrong furnace should not need a replacement before the end of that period. In general, Armstrong furnaces are expected to last between 15 and 20 years, with some of them reported lasting over 45 years.

After the 10-year point, as the furnace nears the end of its life expectancy, it can be either replaced or repaired. The primary consideration at this point is the cost, and the Armstrong Air suggests the 50 percent rule, meaning if the repair cost is near or over 50 percent of the furnace’s value, it is time to replace the unit.