A furnace is almost always a background player at home, keeping you warm in the cold winter months. It frequently won't be 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 important to know the evidence of a cracked heat exchanger and what you should do if you believe that is 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 moves through the air ducts. It generally handles this using coils or tubes that warm the air while acting as a barrier to keep gas formed in the combustion chamber, called flue gasses, from leaking out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its key role, it shouldn't come as a surprise that a cracked heat exchanger can pose a risk. Cracks in the heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to circulate across your home. 

For obvious reasons, do NOT use your heating if you believe it has a cracked heat exchanger, as letting it run could make the entire family ill. Reach out to an HVAC professional as soon as possible if you believe your heating has a cracked heat exchanger that needs repair. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace shuts off: Cracks in the heat exchanger could cause your furnace to shut off. 
  • Strange Smells: If the air coming out of your furnace has a powerful chemical scent, it might be evidence gas is slipping through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm initiates or you recognize poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm should go off or household members may struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If the alarm goes off or you feel unusually tired, exit the home right away and then call for help. 
  • Soot: If you find black sooty accumulating on the exterior of your furnace, it’s another sign something could be seriously wrong.

What You Should Do if Your Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, call a professional well versed in furnace installation Omaha as soon as possible so they can inspect your system and, if necessary, perform 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 regularly included in the warranty. You’ll want to check the warranty paperwork on your furnace, because while the warranty may 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 easiest ways to prevent a problem in your furnace overall is with regular furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Calling a certified professional to examine your furnace for worn-out parts, clogged filters and other likely problems can help you avoid 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 aren't a part of the heat exchanger itself, the strain of drawing air through a clogged filter makes your entire furnace work harder to do its job. And the harder your furnace has to work, the more deterioration parts like the heat exchanger will sustain.