Cracked Heat Exchanger: What That Means and What to Do Next

September 20, 2022

A furnace is often a background player in your home, ensuring you're warm in the cold winter months. It often isn't noticed until a malfunction appears.

One cause might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s critical to learn the signs of a cracked heat exchanger and what to do if you are worried that may be the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger helps transition heat from the combustion chamber in your furnace to the air that circulates throughout the ventilation. It generally does this through coils or tubes that warm the air while serving as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from leaking out into your home.

Is a Cracked Heat Exchanger Dangerous?

Because of its important role, it isn't surprising that a cracked heat exchanger can be very dangerous. A crack in the heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to circulate through your home.

For that reason, never run your heater if you think it has a cracked heat exchanger, as this could make the whole family ill. Contact an HVAC professional right away if you think your furnace has a cracked heat exchanger that needs repair.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace switches off: A crack in your heat exchanger can cause your furnace to turn off.
  • Strange Smells: If the air leaving your furnace has an intense chemical scent, it could be an indicator that gasses are leaking through cracks in your heat exchanger. These byproducts, which will often smell like formaldehyde, are a major warning sign.
  • Carbon monoxide alarm initiates or you feel poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm could go off or family members may struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel unusually tired, get out of the home right away and then call for help.
  • Soot: If you see black sooty buildup around the exterior of your furnace, it’s more evidence something could be seriously wrong.

What You Should Do if the Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, hire a professional with extensive experience in furnace installation Grand Prairie as soon as possible so they can examine your system and, if necessary, handle a furnace heat exchanger replacement. Costs often fluctuate depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.

However, the good news is that heat exchangers are generally covered by the warranty. It's a good idea to check the warranty paperwork on your furnace, since while the warranty may not cover the entire cost of repairs, it could significantly reduce your bill.

How to Avoid a Cracked Heat Exchanger in Your Home

One of the most convenient ways to minimize the risk of problems in your furnace overall is via routine furnace maintenance. Furnaces provide the best possible return on investment when they run efficiently. Calling a trained professional to examine your furnace for old parts, clogs in the air filters and other likely problems can help you avoid getting a big bill later on.

It’s also a good idea to review your furnace filters every few months – it’s encouraged some filters be replaced every 90 days or sooner if they are dirty or grimy. While the filters aren't a part of the heat exchanger itself, the strain of dragging air through a clogged filter makes the entire furnace work longer to accomplish its job. And the harder your furnace works, the more strain parts like the heat exchanger will endure.