A furnace is usually a background player in your home, keeping you warm across the cold winter months. It frequently doesn’t get noticed until something breaks down. 

One source may 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 helps transition heat from the combustion chamber inside your furnace to the air that moves inside the ventilation. It typically accomplishes this with coils or tubes that heat the air while acting as a barrier to keep the gasses created in the combustion chamber, called flue gasses, from escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its important role, it isn't surprising that a cracked heat exchanger can pose a risk. Cracks in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to flow through your home. 

For that reason, do NOT run your furnace if you suspect it has a cracked heat exchanger, as doing so could make your entire household sick. Call an HVAC professional right away if you think your heater has a cracked heat exchanger that needs to be repaired. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace switches off: Cracks in the heat exchanger may cause your furnace to turn off. 
  • Unusual Smells: If the air coming out of your furnace has a powerful chemical odor, it could be an indicator that gas is leaking through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm initiates or you notice health problems: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm could go off or household members could struggle with signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel unwell, get out of the home right away and then call for help. 
  • Soot: If you find black sooty collecting near the exterior of your furnace, it’s another sign something could be seriously wrong.

What You Can Do if Your Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, hire a pro experienced in furnace installation Thousand Palms as soon as possible so they can examine your system and, if required, handle a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are often protected by the warranty. It's a good idea to review the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it can significantly lower your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the most convenient ways to prevent a problem in your furnace overall is via routine furnace maintenance. Furnaces offer the most benefits when they run efficiently. Hiring a certified professional to inspect your furnace for old parts, clogs in the air filters and other potential problems can help you avoid getting a big bill later on.  

It’s also helpful to take a look at 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 pulling air through a clogged filter makes your entire furnace work harder to complete its job. And the harder your furnace works, the more deterioration components like the heat exchanger will sustain.