A furnace is almost always a background player at home, ensuring you're warm in the cold winter months. It frequently isn't noticed until something goes wrong. 

One source may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to learn the evidence of a cracked heat exchanger and what you can do if you are worried 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 flows inside the ventilation. It usually does this with coils or tubes that heat up the air while serving as a barrier to keep byproducts produced in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Given its important role, it shouldn't come as a surprise that a broken heat exchanger can pose a risk. A crack in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to be distributed throughout your home. 

For this reason, never turn on your furnace if you believe it has a cracked heat exchanger, as letting it run could make the entire family ill. Reach out to an HVAC professional as soon as possible if you think your furnace has a cracked heat exchanger that should be repaired. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace switches off: Cracks in the heat exchanger may cause your furnace to shut off. 
  • Odd Smells: If the air coming out of your furnace has an intense chemical odor, it might be evidence gasses are slipping 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 recognize poisoning symptoms: If a cracked heat exchanger is releasing carbon monoxide inside your home, your carbon monoxide alarm could go off or family members might experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unwell, leave the home as soon as you can and then call for help. 
  • Soot: If you spot black sooty buildup near the exterior of your furnace, it’s an indication something might be seriously wrong.

What to Do if a Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, hire a professional with extensive experience in furnace installation West Columbia right away so they can take a look at your system and, if necessary, handle a furnace heat exchanger replacement. Costs often fluctuate 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 generally protected by the warranty. You should confirm the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it can significantly shrink your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the most convenient ways to avoid problems in your furnace overall is through regular furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Hiring a skilled professional to examine your furnace for broken-down parts, clogs in the air filters and other likely problems can keep you from getting a big bill later on.  

It’s also beneficial to review your furnace filters every few months – it’s recommended some filters be changed 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 do its job. And the harder your furnace has to work, the more deterioration parts like the heat exchanger will sustain.