7 Signs Your Furnace is About to Fail

As the temperatures drop and winter settles in, your home’s furnace becomes a crucial component in keeping your living space warm and comfortable. However, like any mechanical system, furnaces can experience issues over time. Recognizing the signs of a failing furnace is essential to prevent unexpected breakdowns and ensure your home stays cozy throughout the winter months. In this article, we’ll explore some common indicators that your furnace may be on the brink of failure.

  1. Age of the Furnace: One of the most straightforward indicators of potential furnace problems is its age. Typically, furnaces have a lifespan of 15 to 20 years. As they approach the end of their operational life, they become more prone to malfunctions. If your furnace is reaching the upper limit of its lifespan, it’s wise to pay extra attention to other signs of failure.
  2. Increased Energy Bills: A sudden spike in your energy bills without a corresponding increase in usage could be a sign of a struggling furnace. As furnaces age and lose efficiency, they often require more energy to generate the same amount of heat. If you notice a significant and unexplained increase in your heating costs, it’s worth investigating the health of your furnace.
  3. Strange Noises: Unusual sounds emanating from your furnace can indicate various issues, from worn-out components to imminent failure. Banging, clanking, popping, or squealing noises are often signs that something is amiss. Ignoring these sounds may lead to more extensive damage and a higher repair bill.
  4. Inconsistent Heating: If you find that some rooms in your home are warmer than others or if your thermostat seems to have difficulty maintaining a consistent temperature, your furnace may be struggling. Inconsistent heating could be the result of a malfunctioning thermostat, a failing blower motor, or issues with the ductwork.
  5. Frequent Repairs: A well-maintained furnace should not require constant repairs. If you find yourself calling in technicians regularly to fix various issues, it might be more cost-effective to consider a replacement. Frequent breakdowns can be a clear indication that your furnace is nearing the end of its service life.
  6. Yellow Pilot Light: In a gas furnace, the pilot light should burn blue. If it appears yellow, it could indicate the presence of carbon monoxide. Carbon monoxide is a colorless and odorless gas that can be extremely dangerous. If you notice a yellow pilot light, it’s crucial to shut off the furnace immediately and seek professional assistance.
  7. Visible Signs of Rust or Cracks: Physically inspecting your furnace for signs of deterioration is important. Rust on the furnace’s exterior or visible cracks in the combustion chamber can indicate corrosion and potential failure. Rust weakens the metal components, and cracks can allow dangerous gases to escape.


Ignoring the signs of a failing furnace can lead to inconvenient breakdowns and chilly nights. Regular maintenance and prompt attention to any red flags can extend the life of your furnace and save you from unexpected repair costs. If you notice any of the signs mentioned above, it’s advisable to consult with a professional HVAC technician at Gem Heating & Air Conditioning who can help to assess the health of your furnace and discuss potential solutions, which may include repair or replacement. A well-functioning furnace not only keeps your home warm but also ensures the safety and comfort of your household during the winter months.