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

September 20, 2022

A furnace is usually a background player in your home, ensuring you're warm in the cold winter months. It often won't be noticed until something breaks down.

One source may be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s important to learn the symptoms of a cracked heat exchanger and what you can do if you suspect that may be the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger helps transition heat from the combustion chamber of your furnace to the air that circulates inside the air ducts. It typically accomplishes this via coils or tubes that warm the air while serving as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from getting out into your home.

Is a Cracked Heat Exchanger Dangerous?

Given its important role, it’s no surprise that a damaged heat exchanger can be very dangerous. A crack in the heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to be distributed throughout your home.

For that reason, never turn on your furnace if you believe it has a cracked heat exchanger, as this could make your entire family sick. Call an HVAC professional right away if you believe your heating has a cracked heat exchanger that should be repaired.

Four Warning Signs of a Cracked Heat Exchanger:

  • Furnace switches off: A cracked heat exchanger can cause your furnace to shut off.
  • Strange Smells: If the air escaping your furnace has a powerful chemical scent, it may be an indicator that gas is seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a major warning sign.
  • Carbon monoxide alarm goes off or you feel poisoning symptoms: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm may go off or family members might experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unwell, get out of the home right away and then call for help.
  • Soot: If you find black sooty buildup on the exterior of your furnace, it’s more evidence something could be seriously wrong.

What You Can Do if a Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, hire a pro experienced in furnace installation Cape Coral as soon as possible so they can take a look at your system and, if necessary, perform a furnace heat exchanger replacement. Costs often fluctuate depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.

Estimates aside, the good news is that heat exchangers are often covered by the warranty. You’ll want to check the warranty paperwork on your furnace, because while the warranty won't always cover the entire cost of repairs, it could significantly shrink your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the easiest ways to minimize the risk of problems in your furnace overall is through regular furnace maintenance. Furnaces provide the best possible return on investment when they run efficiently. Calling a certified professional to check your furnace for broken-down parts, clogs in the air filters and other likely problems can help you avoid getting a big bill later on.

It’s also helpful to review your furnace filters every few months – it’s ideal some filters be changed every 90 days or sooner if they are dirty or grimy. While the filters aren't connected to the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work more vigorously to do its job. And the harder your furnace works, the more strain components like the heat exchanger will endure.