A furnace is almost always a background player in your home, keeping you warm in the cold winter months. It regularly doesn’t get noticed until something goes wrong. 

One cause 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 you should do if you believe that may be 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 ventilation. It typically does this via coils or tubes that warm the air while functioning as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its central role, it’s no surprise that a cracked heat exchanger can pose a risk. A damaged heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to be distributed across your home. 

For this reason, do NOT run your heater if you think you're dealing with a cracked heat exchanger, as doing so could make your entire household sick. Call an HVAC professional as soon as possible if you believe your furnace has a cracked heat exchanger that needs to be repaired. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger may cause your furnace to turn off. 
  • Unusual Smells: If the air coming out of your furnace has an intense chemical scent, it may be a sign gas is slipping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm is triggered or you feel health problems: If a cracked heat exchanger is relieving carbon monoxide into your home, your carbon monoxide alarm should go off or family members might start experiencing 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 as soon as you can and then call for help. 
  • Soot: If you see black sooty collecting near the exterior of your furnace, it’s another sign something may be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, hire a professional with extensive experience in furnace installation Chadron as soon as possible so they can examine your system and, if necessary, start a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000. 

However, the good news is that heat exchangers are often protected by the warranty. You should check the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it can significantly shrink your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the most convenient ways to avoid problems in your furnace overall is through consistent furnace maintenance. Furnaces provide the best possible return on investment when they run efficiently. Calling a skilled 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 take a look at your furnace filters every few months – it’s ideal some filters be changed every 90 days or sooner if they are dirty or grimy. While the filters are not part of the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work harder to accomplish its job. And the harder your furnace needs to run, the more strain pieces like the heat exchanger will sustain.