A furnace is almost always a background player for your home, keeping you warm in the cold winter months. It often 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 signs of a cracked heat exchanger and what you should do if you suspect that may be the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps transition heat from the combustion chamber of your furnace to the air that flows inside the ventilation. It generally handles this through coils or tubes that heat the air while acting as a barrier to keep gas produced in the combustion chamber, called flue gasses, from leaking 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 crack in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to circulate throughout your home. 

For that reason, do NOT run your furnace if you think it has a cracked heat exchanger, as doing so could make the entire family ill. Contact an HVAC professional as soon as possible if you are worried your furnace has a cracked heat exchanger that needs repair. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: A cracked heat exchanger may cause your furnace to switch off. 
  • Strange Smells: If the air coming out of your furnace has an intense chemical odor, it might be an indicator that gasses are seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm initiates or you notice health problems: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm could go off or family members may experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an alarm goes off or you feel sick, get out of the home immediately and then call for help. 
  • Soot: If you notice black sooty accumulating on the exterior of your furnace, it’s an indication something might be seriously wrong.

What You Should Do if the Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, hire a pro with extensive experience in furnace installation Port Clinton right away so they can examine your system and, if required, handle a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates often hover around $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are often covered by the warranty. You’ll want to check the warranty paperwork on your furnace, since while the warranty might 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 easiest ways to avoid problems in your furnace overall is through consistent furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Contacting a certified professional to inspect your furnace for worn-out parts, dirty filters and other likely problems can help you avoid getting a big bill later on.  

It’s also beneficial to inspect 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 your entire furnace work longer to complete its job. And the harder your furnace needs to run, the more wear and tear parts like the heat exchanger will endure.