A furnace is almost always a background player for your home, helping keep you warm during the cold winter months. It often won't be noticed until something goes wrong. 

One source may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to familiarize yourself with 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 of your furnace to the air that flows through the air ducts. It typically does this using coils or tubes that warm the air while acting as a barrier to keep gas formed in the combustion chamber, called flue gasses, from escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its key role, it isn't surprising that a cracked heat exchanger can pose a risk. A damaged heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to circulate throughout your home. 

For this reason, never use your heater if you suspect you're dealing with a cracked heat exchanger, as this could make the entire family ill. Call an HVAC professional right away if you think your heating has a cracked heat exchanger that needs repair. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger can cause your furnace to turn off. 
  • Unusual Smells: If the air coming out of your furnace has an intense chemical smell, it could be evidence gasses are leaking through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm goes off or you notice poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm should go off or family members might 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, exit the home right away and then call for help. 
  • Soot: If you find black sooty collecting near 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 professional well versed in furnace installation Houston right away so they can examine your system and, if required, start a furnace heat exchanger replacement. Costs often 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 included in the warranty. You’ll want to confirm the warranty paperwork on your furnace, as while the warranty may not cover the entire cost of repairs, it can significantly reduce 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 through routine furnace maintenance. Furnaces work the best when they operate efficiently. Contacting a trained professional to inspect your furnace for old parts, clogged 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 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 dragging air through a clogged filter makes the entire furnace work harder to accomplish its job. And the harder your furnace needs to run, the more deterioration parts like the heat exchanger will experience.