Cracked Heat Exchanger: What That Means and What You can Do Next

September 20, 2022

A furnace is usually a background player in your home, ensuring you're warm during the cold winter months. It often isn't noticed until something goes wrong.

One root cause might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to know the symptoms of a cracked heat exchanger and what you should do if you are worried that may be the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger helps move heat from the combustion chamber of your furnace to the air that circulates inside the ventilation. It generally accomplishes this with coils or tubes that heat up the air while functioning as a barrier to keep gas created in the combustion chamber, called flue gasses, from escaping out into your home.

Is a Cracked Heat Exchanger Dangerous?

Because of its central role, it isn't surprising that a damaged heat exchanger can be hazardous. Cracks in the heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to be distributed across your home.

For that reason, don't ever run your heater if you believe you're dealing with a cracked heat exchanger, as this could make your entire family ill. Reach out to an HVAC professional as soon as possible if you are worried your heater has a cracked heat exchanger that should be repaired.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace switches off: A crack in your heat exchanger may cause your furnace to switch off.
  • Strange Smells: If the air escaping your furnace has a powerful chemical odor, it may be a sign gas is slipping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm initiates or you notice symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm may go off or family members might start experiencing signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If your alarm goes off or you feel unusually tired, leave the home immediately and then call for help.
  • Soot: If you notice black sooty collecting on the exterior of your furnace, it’s another sign something may be seriously wrong.

What to Do if a Furnace Heat Exchanger is Cracked

If you believe your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation Florissant as soon as possible so they can examine your system and, if necessary, perform a furnace heat exchanger replacement. Costs should vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.

Fortunately, the good news is that heat exchangers are generally included in the warranty. You should confirm the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it still may significantly lower your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the best ways to minimize the risk of problems in your furnace overall is via routine furnace maintenance. Furnaces offer the most benefits when they run efficiently. Contacting a certified professional to check your furnace for worn-out parts, clogged filters and other potential problems can keep you from getting a big bill later on.

It’s also a good idea to take a look at your furnace filters every few months – it’s ideal some filters be swapped out 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 drawing air through a clogged filter makes the entire furnace work harder to accomplish its job. And the harder your furnace has to work, the more deterioration parts like the heat exchanger will endure.