A furnace is almost always a background player in your home, helping keep you warm in the cold winter months. It often doesn’t get noticed until a malfunction appears. 

One root cause might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s important to know the evidence of a cracked heat exchanger and what you can 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 in your furnace to the air that flows through the ventilation. It generally handles this with 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 important role, it isn't surprising that a broken heat exchanger can be hazardous. A damaged heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to circulate through your home. 

For obvious reasons, do NOT turn on your furnace if you think there's a crack in the heat exchanger, as letting it run could make the whole household sick. Call an HVAC professional as soon as possible if you think your heating has a cracked heat exchanger that should be repaired. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger may cause your furnace to switch off. 
  • Unusual Smells: If the air escaping your furnace has a powerful chemical smell, it may be an indicator that gasses are seeping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm goes off or you recognize health problems: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm may go off or family members could start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel sick, exit the home as soon as you can and then call for help. 
  • Soot: If you notice black sooty buildup around the exterior of your furnace, it’s another sign something could be seriously wrong.

What You Can Do if the Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, hire a pro well versed in furnace installation Wyandotte as soon as possible so they can take a look at your system and, if required, perform a furnace heat exchanger replacement. Costs often fluctuate depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000. 

However, the good news is that heat exchangers are often covered by the warranty. You’ll want to review the warranty paperwork on your furnace, as while the warranty might not cover the entire cost of repairs, it could significantly lower your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the best ways to prevent a problem in your furnace overall is via routine furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Contacting a skilled professional to check your furnace for old parts, clogs in the air filters and other potential problems can keep you from getting a big bill later on.  

It’s also helpful 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 dragging air through a clogged filter makes the entire furnace work more vigorously to accomplish its job. And the harder your furnace needs to run, the more deterioration components like the heat exchanger will experience.