A furnace is usually a background player at home, helping keep you warm during the cold winter months. It regularly won't be noticed until a malfunction appears. 

One source may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s worthwhile to familiarize yourself with the symptoms of a cracked heat exchanger and what you can do if you believe that is 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 inside the ventilation. It usually handles this using coils or tubes that warm the air while serving as a barrier to keep the gasses produced in the combustion chamber, called flue gasses, from escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its central role, it’s no surprise that a broken heat exchanger can be hazardous. 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 turn on your heater if you suspect you're dealing with a cracked heat exchanger, as letting it run could make the whole family sick. Contact an HVAC professional right away if you are worried your furnace has a cracked heat exchanger that needs repair. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace turns off: A cracked heat exchanger may cause your furnace to switch off. 
  • Unusual Smells: If the air escaping your furnace has a powerful chemical scent, it could be a sign gasses are slipping through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm goes off or you feel poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide inside your home, your carbon monoxide alarm could go off or household members might struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unusually tired, exit the home immediately and then call for help. 
  • Soot: If you find black sooty accumulating near the exterior of your furnace, it’s more evidence something might be seriously wrong.

What You Can Do if the Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, hire a professional experienced in furnace installation Cedar Rapids as soon as possible so they can examine your system and, if required, start a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

However, the good news is that heat exchangers are regularly covered by 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 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 through regular furnace maintenance. Furnaces work the best when they work efficiently. Calling a skilled professional to check your furnace for worn-out parts, clogs in the air filters and other potential problems can keep you from getting a big bill later on.  

It’s also a good idea to inspect your furnace filters every few months – it’s encouraged some filters be swapped out 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 drawing air through a clogged filter makes your entire furnace work harder to accomplish its job. And the harder your furnace works, the more strain pieces like the heat exchanger will endure.