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

September 20, 2022

A furnace is almost always a background player in your home, ensuring you're warm in the cold winter months. It frequently won't be noticed until something breaks down.

One source might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s critical to know the symptoms of a cracked heat exchanger and what to 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 inside your furnace to the air that flows throughout the ventilation. It generally does this through coils or tubes that heat the air while serving as a barrier to keep gas formed in the combustion chamber, called flue gasses, from escaping out into your home.

Is a Cracked Heat Exchanger Dangerous?

Thanks to its central role, it shouldn't come as a surprise that a damaged heat exchanger can pose a risk. A crack in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home.

For this reason, never turn on your heating if you suspect there's a crack in the heat exchanger, as letting it run could make your entire household sick. Contact an HVAC professional as soon as possible if you believe your heating has a cracked heat exchanger that should be repaired.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace shuts off: A crack in your heat exchanger can cause your furnace to turn off.
  • Odd Smells: If the air escaping your furnace has a strong chemical smell, it may be evidence gas is slipping 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 symptoms of poisoning: If a cracked heat exchanger is relieving carbon monoxide inside your home, your carbon monoxide alarm should go off or household members might experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel unusually tired, leave the home as soon as you can and then call for help.
  • Soot: If you see black sooty accumulating near the exterior of your furnace, it’s an indication something may be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, hire a professional experienced in furnace installation Zelienople as soon as possible so they can inspect your system and, if needed, handle a furnace heat exchanger replacement. Costs should vary depending on the situation, but estimates often hover around $1,000 to $3,000.

Fortunately, the good news is that heat exchangers are often covered by the warranty. You should check the warranty paperwork on your furnace, as while the warranty may not cover the entire cost of repairs, it could significantly reduce your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the most convenient ways to prevent a problem in your furnace overall is through consistent furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Calling a certified professional to examine your furnace for old parts, dirty filters and other potential problems can keep you from getting a big bill later on.

It’s also a good idea to inspect 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 aren't a part of the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work harder to accomplish its job. And the harder your furnace has to work, the more wear and tear pieces like the heat exchanger will endure.