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

September 20, 2022

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

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

What Is a Heat Exchanger in a Furnace?

A heat exchanger helps move heat from the combustion chamber of your furnace to the air that circulates inside the air ducts. It typically does this through coils or tubes that heat the air while acting as a barrier to keep gas formed in the combustion chamber, called flue gasses, from getting 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 be very dangerous. Cracks in the heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to circulate across your home.

For that reason, never use your furnace if you suspect it has a cracked heat exchanger, as this could make your entire family ill. Reach out to an HVAC professional right away if you believe your furnace has a cracked heat exchanger that should be repaired.

Four Warning Signs of a Cracked Heat Exchanger:

  • Furnace shuts off: Cracks in the heat exchanger could cause your furnace to turn off.
  • Odd Smells: If the air escaping your furnace has an intense chemical smell, it might be evidence gasses are seeping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm initiates or you feel health problems: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm may go off or family members could start experiencing signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel sick, exit the home as soon as you can and then call for help.
  • Soot: If you find black sooty collecting on the exterior of your furnace, it’s another sign something may be seriously wrong.

What You Should Do if the Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, contact a professional with extensive experience in furnace installation Norton as soon as possible so they can take a look at your system and, if required, handle a furnace heat exchanger replacement. Costs should vary depending on the situation, but estimates often hover around $1,000 to $3,000.

However, the good news is that heat exchangers are often covered by the warranty. It's a good idea to check the warranty paperwork on your furnace, since while the warranty may not cover the entire cost of repairs, it still may significantly reduce your bill.

How to Avoid a Cracked Heat Exchanger in Your Home

One of the best ways to prevent a problem in your furnace overall is via consistent furnace maintenance. Furnaces work the best when they work efficiently. Hiring a trained professional to check your furnace for old parts, dirty filters and other likely problems can keep you from getting a big bill later on.

It’s also beneficial to inspect your furnace filters every few months – it’s encouraged some filters be replaced 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 harder to do its job. And the harder your furnace needs to run, the more deterioration parts like the heat exchanger will experience.