Cracked Heat Exchanger: What It Means and What You Should Do Next

September 20, 2022

A furnace is usually a background player for your home, helping keep you warm during the cold winter months. It regularly isn't noticed until a malfunction appears.

One root cause may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s worthwhile to familiarize yourself with the signs of a cracked heat exchanger and what you should do if you suspect that might 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 throughout the ventilation. It typically does this through coils or tubes that warm the air while acting as a barrier to keep the gasses produced 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. A crack in the heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to circulate through your home.

For this reason, don't ever turn on your heating if you suspect there's a crack in the heat exchanger, as this could make the entire family sick. Contact an HVAC professional right away if you are worried your heating has a cracked heat exchanger that needs repair.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace switches off: A cracked heat exchanger can cause your furnace to turn off.
  • Unusual Smells: If the air coming out of your furnace has a powerful chemical smell, it could be an indicator that gas is slipping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a common warning sign.
  • Carbon monoxide alarm initiates or you recognize health problems: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm may go off or family members may struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel unwell, get out of the home right away and then call for help.
  • Soot: If you find black sooty buildup around the exterior of your furnace, it’s more evidence something could be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked

If you believe your furnace has a cracked heat exchanger, contact a professional with extensive experience in furnace installation Sandpoint as soon as possible so they can take a look at your system and, if necessary, perform a furnace heat exchanger replacement. Costs often vary 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 generally protected by the warranty. You should confirm the warranty paperwork on your furnace, as while the warranty may not cover the entire cost of repairs, it still may significantly reduce your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the most convenient ways to minimize the risk of problems in your furnace overall is via routine furnace maintenance. Furnaces work the best when they work efficiently. Calling a certified professional to check your furnace for old parts, clogged filters and other likely 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 replaced 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 longer to do its job. And the harder your furnace has to work, the more deterioration parts like the heat exchanger will experience.