A furnace is often a background player at home, helping keep you warm in the cold winter months. It regularly isn't noticed until a malfunction appears. 

One cause may be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s critical to familiarize yourself with the signs of a cracked heat exchanger and what you can do if you suspect that is the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps move heat from the combustion chamber inside your furnace to the air that flows throughout the system. It usually handles this via coils or tubes that heat up the air while functioning as a barrier to keep byproducts created 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 shouldn't come as a surprise that a cracked heat exchanger can pose a risk. Cracks in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to be distributed across your home. 

For obvious reasons, do NOT run your heating if you suspect you're dealing with a cracked heat exchanger, as letting it run could make your entire household sick. Call an HVAC professional right away if you think your furnace has a cracked heat exchanger that needs repair. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger could cause your furnace to turn off. 
  • Odd Smells: If the air escaping your furnace has a strong chemical smell, it could be evidence gasses are slipping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm is triggered or you notice poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm could go off or household members might struggle with signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If your alarm goes off or you feel sick, leave the home immediately and then call for help. 
  • Soot: If you notice black sooty collecting on the exterior of your furnace, it’s more evidence something might be seriously wrong.

What You Should Do if the Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, call a pro with extensive experience in furnace installation Ellsworth as soon as possible so they can inspect your system and, if needed, perform a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are regularly protected by the warranty. You should review the warranty paperwork on your furnace, because while the warranty may not cover the entire cost of repairs, it still may significantly reduce your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the best ways to minimize the risk of problems in your furnace overall is through consistent furnace maintenance. Furnaces offer the most benefits when they run efficiently. Calling a trained professional to examine your furnace for broken-down parts, dirty filters and other common problems can help you avoid getting a big bill later on.  

It’s also beneficial to review 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 your entire furnace work more vigorously to accomplish its job. And the harder your furnace has to work, the more deterioration parts like the heat exchanger will endure.