A furnace is almost always a background player for your home, keeping you warm in the cold winter months. It frequently won't be noticed until something breaks down. 

One root cause could be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s worthwhile to know the evidence of a cracked heat exchanger and what you can do if you believe that might be 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 moves throughout the air ducts. It usually handles this through coils or tubes that warm the air while acting as a barrier to keep the gasses formed in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its important role, it’s no surprise that a broken heat exchanger can be hazardous. Cracks in the heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to be distributed through your home. 

For that reason, never turn on your heater if you think it has a cracked heat exchanger, as doing so could make the entire household sick. Call an HVAC professional immediately if you believe your furnace has a cracked heat exchanger that should be repaired. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: Cracks in the heat exchanger can cause your furnace to shut off. 
  • Unusual Smells: If the air leaving your furnace has a powerful chemical smell, it could be a sign gasses are seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm is triggered or you feel poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm may go off or family members might start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unwell, exit the home right away and then call for help. 
  • Soot: If you find black sooty accumulating around the exterior of your furnace, it’s more evidence something could be seriously wrong.

What to Do if the Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, call a pro well versed in furnace installation Corpus Christi right away so they can take a look at your system and, if needed, handle a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Fortunately, 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 won't always cover the entire cost of repairs, it could significantly shrink 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 regular furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Calling a certified professional to inspect your furnace for broken-down parts, clogs in the air filters and other potential problems can help you avoid getting a big bill later on.  

It’s also a good idea 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 connected to the heat exchanger itself, the strain of dragging air through a clogged filter makes the entire furnace work longer to accomplish its job. And the harder your furnace needs to run, the more wear and tear parts like the heat exchanger will experience.