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

September 20, 2022

A furnace is often a background player at home, ensuring you're warm in the cold winter months. It often doesn’t get noticed until something goes wrong.

One source might be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to know the signs of a cracked heat exchanger and what to do if you believe that is the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger transfers heat from the combustion chamber in your furnace to the air that circulates inside the ventilation. It generally handles this through coils or tubes that warm the air while serving as a barrier to keep the gasses formed in the combustion chamber, called flue gasses, from escaping out into your home.

Is a Cracked Heat Exchanger Dangerous?

Thanks to its important role, it isn't surprising that a damaged heat exchanger can be hazardous. Cracks in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to flow across your home.

For that reason, don't ever use your furnace if you believe it has a cracked heat exchanger, as letting it run could make the whole family ill. Contact an HVAC professional immediately if you believe your furnace has a cracked heat exchanger that should be repaired.

Four Signs of a Cracked Heat Exchanger:

  • Furnace switches off: A crack in your heat exchanger could cause your furnace to switch off.
  • Odd Smells: If the air escaping your furnace has a strong chemical smell, it might be a sign gas is slipping through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm is triggered or you notice health problems: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm should go off or family members may experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel unwell, get out of the home immediately and then call for help.
  • Soot: If you find black sooty buildup on the exterior of your furnace, it’s an indication something may be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, contact a professional well versed in furnace installation Magnolia right away so they can examine your system and, if needed, handle a furnace heat exchanger replacement. Costs often differ 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 regularly covered by the warranty. You should check the warranty paperwork on your furnace, as while the warranty might not cover the entire cost of repairs, it could significantly lower your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the best ways to avoid problems in your furnace overall is with consistent furnace maintenance. Furnaces offer the most benefits when they run efficiently. Contacting a certified professional to examine your furnace for worn-out parts, clogged filters and other likely problems can help you avoid getting a big bill later on.

It’s also beneficial to review your furnace filters every few months – it’s recommended 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 dragging air through a clogged filter makes the entire furnace work harder to complete its job. And the harder your furnace needs to run, the more strain pieces like the heat exchanger will experience.