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

September 20, 2022

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

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

What Is a Heat Exchanger in a Furnace?

A heat exchanger helps move heat from the combustion chamber in your furnace to the air that moves through the air ducts. It typically does this via coils or tubes that warm the air while serving as a barrier to keep the gasses created in the combustion chamber, called flue gasses, from leaking out into your home.

Is a Cracked Heat Exchanger Dangerous?

Thanks to its key role, it isn't surprising that a cracked heat exchanger can pose a risk. 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, do NOT turn on your heating if you believe it has a cracked heat exchanger, as doing so could make the entire household ill. Call an HVAC professional right away if you believe your heating has a cracked heat exchanger that needs repair.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace turns off: A cracked heat exchanger could cause your furnace to switch off.
  • Odd Smells: If the air leaving your furnace has a powerful chemical scent, it could be evidence gas is seeping through cracks in your heat exchanger. These byproducts, which will often smell like formaldehyde, are a common warning sign.
  • Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is releasing carbon monoxide inside your home, your carbon monoxide alarm could go off or household members might struggle with signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If your alarm goes off or you feel unwell, leave the home right away and then call for help.
  • Soot: If you find black sooty collecting around the exterior of your furnace, it’s an indication something could be seriously wrong.

What You Can Do if Your Furnace Heat Exchanger is Cracked

If you believe your furnace has a cracked heat exchanger, hire a professional experienced in furnace installation Marshfield right away so they can take a look at your system and, if needed, perform a furnace heat exchanger replacement. Costs will differ 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 regularly covered by the warranty. You should check the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it still may significantly shrink your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the best ways to prevent a problem in your furnace overall is through consistent furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Calling a trained professional to check your furnace for old parts, clogged filters and other potential problems can keep you from getting a big bill later on.

It’s also a good idea to inspect your furnace filters every few months – it’s ideal 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 pulling air through a clogged filter makes your entire furnace work harder to accomplish its job. And the harder your furnace has to work, the more strain pieces like the heat exchanger will endure.