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

September 20, 2022

A furnace is almost always a background player at home, ensuring you're warm in the cold winter months. It frequently isn't noticed until something goes wrong.

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

What Is a Heat Exchanger in a Furnace?

A heat exchanger helps transition heat from the combustion chamber in your furnace to the air that flows throughout the system. It generally handles this via coils or tubes that warm the air while functioning as a barrier to keep the gasses created 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 broken heat exchanger can pose a risk. A damaged heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to be distributed through your home.

For that reason, never use your heating if you believe you're dealing with a cracked heat exchanger, as letting it run could make the entire household sick. Call an HVAC professional as soon as possible if you think your furnace has a cracked heat exchanger that needs repair.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace turns off: Cracks in the heat exchanger could cause your furnace to turn off.
  • Unusual Smells: If the air coming out of your furnace has a powerful chemical odor, it may be an indicator that gas is leaking 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 recognize symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm may go off or household members could experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel sick, get out of the home immediately and then call for help.
  • Soot: If you notice black sooty accumulating around the exterior of your furnace, it’s more evidence something might be seriously wrong.

What to Do if a Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, call a pro experienced in furnace installation Marshalltown as soon as possible so they can examine your system and, if required, 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.

Estimates aside, the good news is that heat exchangers are often protected by the warranty. You’ll want to confirm the warranty paperwork on your furnace, because while the warranty might 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 best ways to prevent a problem in your furnace overall is through regular furnace maintenance. Furnaces work the best when they work efficiently. Contacting a trained professional to examine your furnace for worn-out parts, clogged filters and other common problems can keep you from getting a big bill later on.

It’s also beneficial to take a look at your furnace filters every few months – it’s recommended some filters be changed every 90 days or sooner if they are dirty or grimy. While the filters are not part of the heat exchanger itself, the strain of dragging air through a clogged filter makes the entire furnace work longer to complete its job. And the harder your furnace needs to run, the more wear and tear parts like the heat exchanger will sustain.