Safety should be our first concern. An old furnace should be checked for cracks in the heat exchanger. The biggest danger is Carbon Monoxide Poison. If you question your furnace, you should have it inspected by a professional. Call Foothills Mechanical Service for a complete furnace check out. New furnaces have stainless steel heat exchangers that don’t have heat exchanger problems. Improve Furnace Efficiency by 15 to 20%, get a new equipment warranty, and insure your family’s safety. Why wouldn’t you replace that old furnace?