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

September 20, 2022

A furnace is almost always a background player at home, helping keep you warm during the cold winter months. It regularly isn't noticed until something goes wrong.

One source might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s important to know the evidence of a cracked heat exchanger and what you should do if you believe that might be the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger transfers heat from the combustion chamber inside your furnace to the air that flows inside the air ducts. It typically accomplishes this via coils or tubes that heat up the air while functioning as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from escaping out into your home.

Is a Cracked Heat Exchanger Dangerous?

Because of its key role, it’s no surprise that a damaged heat exchanger can be hazardous. A crack in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to be distributed through your home.

For obvious reasons, don't ever use your furnace if you suspect there's a crack in the heat exchanger, as this could make the whole household ill. Contact an HVAC professional immediately if you think your furnace has a cracked heat exchanger that needs to be repaired.

Four Signs of a Cracked Heat Exchanger:

  • Furnace turns off: Cracks in the heat exchanger could cause your furnace to turn off.
  • Strange Smells: If the air coming out of your furnace has a powerful chemical odor, it might be a sign gas is leaking through cracks in your heat exchanger. These byproducts, which will often smell like formaldehyde, are a major warning sign.
  • Carbon monoxide alarm is triggered or you notice health problems: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm could go off or family members may start experiencing signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel unwell, leave the home immediately and then call for help.
  • Soot: If you spot black sooty collecting around the exterior of your furnace, it’s an indication something might be seriously wrong.

What to Do if Your Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, call a pro experienced in furnace installation McHenry right away so they can examine your system and, if needed, perform a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000.

Fortunately, the good news is that heat exchangers are generally included in the warranty. You should review the warranty paperwork on your furnace, as while the warranty may not cover the entire cost of repairs, it can significantly lower your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the most convenient ways to avoid problems in your furnace overall is via regular furnace maintenance. Furnaces offer the most benefits when they run efficiently. Hiring a trained professional to inspect your furnace for broken-down parts, clogs in the air filters and other common 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 drawing air through a clogged filter makes the entire furnace work more vigorously to accomplish its job. And the harder your furnace works, the more deterioration parts like the heat exchanger will sustain.