Cracked Heat Exchanger: A Danger to Your Household

Cracked Heat Exchanger: A Danger to Your HouseholdA cracked heat exchanger represents the one single problem that can take your furnace out of operation, even though it probably still runs. The heat exchanger absorbs the heat the fuel creates inside the burner, and as the air blows over the exchanger, it warms and blows through the ductwork. When the heat exchanger has cracks or holes, it can emit carbon monoxide (CO), a highly toxic gas, into your home’s air.


  • CO detectors may sound when the furnace runs.
  • You may hear a popping or banging sound coming from the air handler.
  • An HVAC professional may detect problems with the flame inside the burner.

After the HVAC technician discovers a cracked heat exchanger, he or she has to disable the furnace because CO is such a dangerous gas.

Once detected, options are limited to replacing the heat exchanger or the entire furnace. Unless the appliance is under warranty, furnace replacement usually makes more financial sense than repair. The cost of the part and the labor usually exceed the value of the furnace.


The two leading causes of cracks in the heat exchanger include:

  • Running the system with an excessively dirty air filter. Dirt can cover this part, insulating it and allowing it to get too hot. Over time, the metal weakens and cracks or holes form.
  • Using a furnace that’s outlived its useful life. Over time, metal fatigue affects the heat exchanger since it’s subject to extreme temperature swings.


Changing the air filter for your HVAC system during the heating and cooling seasons keeps your system cleaner and stops much of the household dust from entering it and provides optimal airflow.

Having it serviced by a professional annually. HVAC professionals inspect and deep clean parts of the air handler that are otherwise inaccessible.

Because a cracked heat exchanger is a serious threat to your safety, it’s important to stay on top of filter changes and system maintenance throughout the year. Contact the pros at CCAC to help you safeguard your home in the Coastal Bend area.

Our goal is to help educate our customers in Corpus Christi, Texas about energy and home comfort issues (specific to HVAC systems). For more information about cracked heat exchangers and other HVAC topics, download our free Home Comfort Guide or call us at 361-678-2495.

Credit/Copyright Attribution: “GOLFX/Shutterstock”

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    David Mathewst David Mathews is the owner of CCAC Air Conditioning and Heating. A Corpus Christi native... More »