A furnace is usually a background player in your home, ensuring you're warm during the cold winter months. It often isn't noticed until something breaks down. 

One root cause might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s critical to learn the evidence of a cracked heat exchanger and what you should do if you believe that might 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 flows inside the air ducts. It usually accomplishes this via coils or tubes that heat the air while serving 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 shouldn't come as a surprise that a cracked heat exchanger can pose a risk. A crack in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to be distributed throughout your home. 

For this reason, don't ever use your heating if you suspect you're dealing with a cracked heat exchanger, as doing so could make the entire family sick. Reach out to an HVAC professional right away if you are worried your heater has a cracked heat exchanger that needs to be repaired. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: A crack in your heat exchanger may cause your furnace to turn off. 
  • Unusual Smells: If the air escaping your furnace has a powerful chemical scent, it could be evidence gas is seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm goes off or you feel symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm should go off or family members could experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel sick, get out of the home immediately and then call for help. 
  • Soot: If you see black sooty collecting on the exterior of your furnace, it’s an indication something may be seriously wrong.

What to Do if a Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, hire a pro well versed in furnace installation Cottonwood & Prescott as soon as possible so they can take a look at your system and, if needed, perform a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000. 

However, the good news is that heat exchangers are generally protected by the warranty. You should review the warranty paperwork on your furnace, since while the warranty may 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 best ways to prevent a problem in your furnace overall is via consistent furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Calling a certified professional to examine 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 take a look at your furnace filters every few months – it’s encouraged 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 pulling air through a clogged filter makes your entire furnace work harder to complete its job. And the harder your furnace works, the more strain pieces like the heat exchanger will endure.