Understanding When it's Time to Plan for Furnace Replacement

Posted on: 1 February 2021


By the time a furnace is 20 years old, homeowners should start planning for replacement. That's especially true if there have been some malfunctions in recent years and a few calls for repair service. A new furnace will be quieter, more energy-efficient, and will be more unlikely to break down. Old furnaces also can eventually become health hazards.

Energy Efficiency Considerations

Higher energy efficiency means decreased use of heating fuel and lower utility bills than would otherwise be the case. That decrease in fuel usage also is environmentally-friendly. A still-operating furnace manufactured in the 1990s might have an efficiency rating of only 60 percent. In contrast, today's high-efficiency products are rated at 90 to 97 percent. However, they cost more than models with a standard efficiency of 80 percent. That's because these appliances have a secondary heat exchanger to capture the warmth that would otherwise be lost through the exhaust.

Carbon Monoxide

With proper maintenance, heating technicians and equipment owners can keep a furnace operating for many years beyond the typical longevity. Eventually, though, the furnace must be replaced. The possibility of a carbon monoxide leak increases as the heat exchanger ages past the usual lifespan. Heating technicians can advise their customers well beforehand that it's time to plan for furnace replacement. They identify the signs of wear during the annual maintenance appointment and when they are called to perform repairs. 

Technicians also identify when the heat exchanger is at risk of cracking. Their customers should not delay any longer at this point. If the exchanger cracks, the blower sends exhaust gas into the building through the vents. A carbon monoxide detector alerts the household, but not everyone has this device. In addition, cheaper monitors may not detect the gas until levels are high enough to make people sick. Young children and family pets are at greater risk of serious symptoms because of their small size. A rattling noise when the furnace first starts up and before the blower motor turns on is a distinct symptom of a cracked heat exchanger. The furnace must be shut off because it is no longer safe to operate.

In the Future

Homeowners who are fortunate enough to have a 20-year-old furnace in good working order have likely been very conscientious about routine maintenance. They've changed the air filter as recommended and had a heating technician perform maintenance service each year. If they continue this behavior with their new appliance, they should experience excellent results again with the higher quality equipment now available.