A furnace is usually a background player for your home, ensuring you're warm across the cold winter months. It frequently isn't noticed until a malfunction appears. 

One cause may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to know the evidence of a cracked heat exchanger and what you should do if you suspect 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 system. It usually handles this through coils or tubes that heat the air while serving as a barrier to keep gas created 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 damaged heat exchanger can be hazardous. A damaged heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home. 

For this reason, never turn on your furnace if you believe you're dealing with a cracked heat exchanger, as letting it run could make the whole family ill. Reach out to 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 could cause your furnace to shut off. 
  • Unusual Smells: If the air escaping your furnace has a strong chemical smell, it may be an indicator that gas is seeping through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a major 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 should go off or family members might struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel unwell, exit the home immediately and then call for help. 
  • Soot: If you notice black sooty buildup on the exterior of your furnace, it’s an indication something might be seriously wrong.

What to 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 Wyandotte right away so they can examine your system and, if necessary, start a furnace heat exchanger replacement. Costs will differ 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 check the warranty paperwork on your furnace, as while the warranty won't always 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 easiest ways to prevent a problem in your furnace overall is via regular furnace maintenance. Furnaces offer the most benefits when they work efficiently. Calling a trained professional to examine your furnace for worn-out parts, clogged filters and other common problems can help you avoid getting a big bill later on.  

It’s also helpful to review your furnace filters every few months – it’s encouraged 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 your entire furnace work harder to do its job. And the harder your furnace works, the more deterioration components like the heat exchanger will endure.