A furnace is often a background player for your home, keeping you warm during the cold winter months. It frequently doesn’t get 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 critical to familiarize yourself with the symptoms of a cracked heat exchanger and what to 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 in your furnace to the air that moves throughout the air ducts. It usually accomplishes this with coils or tubes that heat up the air while serving as a barrier to keep gas created 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 isn't surprising that a damaged heat exchanger can be very dangerous. A damaged heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to be distributed throughout your home. 

For obvious reasons, never run your furnace if you believe you're dealing with a cracked heat exchanger, as this could make the entire household sick. Reach out to an HVAC professional right away if you believe your heating has a cracked heat exchanger that needs repair. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace switches off: A cracked heat exchanger may cause your furnace to shut off. 
  • Strange Smells: If the air escaping your furnace has an intense chemical scent, it could be an indicator that gasses are leaking through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm initiates or you recognize health problems: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm should go off or household members could experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel sick, leave the home right away and then call for help. 
  • Soot: If you see black sooty collecting near the exterior of your furnace, it’s more evidence something might be seriously wrong.

What You Should Do if Your Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, hire a professional experienced in furnace installation Omaha as soon as possible so they can examine your system and, if needed, start 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 regularly included in the warranty. It's a good idea to review the warranty paperwork on your furnace, since 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 best ways to minimize the risk of problems in your furnace overall is through routine furnace maintenance. Furnaces work the best when they operate efficiently. Calling a certified professional to inspect your furnace for old parts, clogged 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 ideal 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 complete its job. And the harder your furnace needs to run, the more wear and tear components like the heat exchanger will sustain.