A furnace is almost always a background player in your home, keeping you warm in the cold winter months. It regularly doesn’t get noticed until a malfunction appears. 

One source might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s critical to know the symptoms of a cracked heat exchanger and what you should do if you believe that is the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger transfers heat from the combustion chamber of your furnace to the air that moves through the ventilation. It generally does 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 leaking out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its important role, it shouldn't come as a surprise that a broken heat exchanger can pose a risk. A damaged heat exchanger can enable dangerous gasses – such as carbon monoxide, which can be lethal – to flow through your home. 

For obvious reasons, do NOT use your heating if you think there's a crack in the heat exchanger, as letting it run could make your entire household ill. Call an HVAC professional right away if you believe your heater has a cracked heat exchanger that should be repaired. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace turns off: A cracked heat exchanger may cause your furnace to turn off. 
  • Strange Smells: If the air coming out of your furnace has an intense chemical odor, it might be a sign gas is leaking through cracks in your heat exchanger. These byproducts, which will often smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm initiates or you notice health problems: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm could go off or household members might experience signs of carbon monoxide poisoning. Side effects 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 spot black sooty accumulating around the exterior of your furnace, it’s an indication something may be seriously wrong.

What You Should Do if the Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, contact a pro with extensive experience in furnace installation Cedar Rapids as soon as possible so they can examine your system and, if needed, start a furnace heat exchanger replacement. Costs should 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 included in the warranty. You should check the warranty paperwork on your furnace, because 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 easiest ways to minimize the risk of problems in your furnace overall is with routine furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Calling a skilled professional to check your furnace for old parts, clogged filters and other common problems can keep you from getting a big bill later on.  

It’s also beneficial to take a look at your furnace filters every few months – it’s ideal some filters be swapped out 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 drawing air through a clogged filter makes the entire furnace work harder to complete its job. And the harder your furnace has to work, the more deterioration parts like the heat exchanger will endure.