A furnace is usually a background player for your home, keeping you warm during the cold winter months. It regularly won't be noticed until something goes wrong. 

One cause might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to learn the symptoms of a cracked heat exchanger and what you should do if you suspect 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 inside the ventilation. It typically accomplishes this through coils or tubes that warm the air while functioning as a barrier to keep byproducts produced 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 damaged heat exchanger can pose a risk. Cracks in the heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to flow through your home. 

For this reason, don't ever use your heater if you suspect you're dealing with a cracked heat exchanger, as doing so could make your entire family ill. Reach out to an HVAC professional as soon as possible if you believe your heater has a cracked heat exchanger that needs to be repaired. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: Cracks in the heat exchanger can cause your furnace to turn off. 
  • Unusual Smells: If the air leaving your furnace has a strong chemical scent, it could be an indicator that gas is slipping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm goes off or you feel poisoning symptoms: If a cracked heat exchanger is releasing carbon monoxide inside your home, your carbon monoxide alarm should go off or family members could struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel unwell, get out of the home immediately and then call for help. 
  • Soot: If you find black sooty buildup on the exterior of your furnace, it’s another sign something might be seriously wrong.

What You Can Do if the Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, hire a pro experienced in furnace installation Big Spring as soon as possible so they can examine your system and, if needed, perform a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are often covered by the warranty. It's a good idea to confirm the warranty paperwork on your furnace, because while the warranty may not cover the entire cost of repairs, it still may significantly shrink your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the best ways to minimize the risk of problems in your furnace overall is with consistent furnace maintenance. Furnaces work the best when they work efficiently. Contacting a trained professional to examine your furnace for old parts, clogs in the air filters and other likely 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 ideal some filters be replaced every 90 days or sooner if they are dirty or grimy. While the filters aren't connected to the heat exchanger itself, the strain of drawing air through a clogged filter makes your entire furnace work longer to accomplish its job. And the harder your furnace needs to run, the more wear and tear pieces like the heat exchanger will sustain.