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 across the cold winter months. It regularly won't be noticed until something breaks down.

One root cause may be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s important to familiarize yourself with the symptoms of a cracked heat exchanger and what you can 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 of your furnace to the air that circulates inside the system. It generally accomplishes this using coils or tubes that warm the air while serving as a barrier to keep gas created in the combustion chamber, called flue gasses, from leaking out into your home.

Is a Cracked Heat Exchanger Dangerous?

Because of its important role, it isn't surprising that a damaged heat exchanger can pose a risk. Cracks in the heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to flow across your home.

For obvious reasons, never run your heater if you believe it has a cracked heat exchanger, as doing so could make your entire household sick. Call an HVAC professional as soon as possible if you think your furnace has a cracked heat exchanger that should be repaired.

Four Warning Signs of a Cracked Heat Exchanger:

  • Furnace switches off: Cracks in the heat exchanger may cause your furnace to turn off.
  • Strange Smells: If the air coming out of your furnace has a powerful chemical smell, it could be an indicator that gasses are slipping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm goes off or you feel symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm should go off or family members might struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unwell, leave the home immediately and then call for help.
  • Soot: If you see black sooty collecting near the exterior of your furnace, it’s more evidence something could be seriously wrong.

What to Do if Your Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, hire a pro well versed in furnace installation Brandon as soon as possible so they can examine your system and, if required, perform a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000.

Estimates aside, the good news is that heat exchangers are generally included in 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 lower your bill.

How to Avoid a Cracked Heat Exchanger in Your Home

One of the easiest ways to avoid problems in your furnace overall is through consistent furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Contacting a trained professional to examine your furnace for worn-out parts, clogged filters and other likely problems can keep you from getting a big bill later on.

It’s also beneficial to review your furnace filters every few months – it’s encouraged 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 drawing 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 strain pieces like the heat exchanger will sustain.