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

One source could be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s critical to familiarize yourself with the evidence 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 in your furnace to the air that flows through the ventilation. It generally does this through coils or tubes that heat up the air while functioning as a barrier to keep gas formed in the combustion chamber, called flue gasses, from leaking out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its important role, it isn't surprising that a cracked heat exchanger can be very dangerous. A crack in the heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to circulate through your home. 

For that reason, don't ever use your heating if you believe you're dealing with a cracked heat exchanger, as letting it run could make your entire household ill. Contact an HVAC professional immediately if you think your heating has a cracked heat exchanger that needs repair. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger can cause your furnace to switch off. 
  • Odd Smells: If the air coming out of your furnace has a strong chemical smell, it could be evidence gasses are leaking through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm initiates or you feel symptoms of poisoning: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm may go off or family members could start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unusually tired, leave the home right away and then call for help. 
  • Soot: If you notice black sooty collecting near the exterior of your furnace, it’s an indication something might be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, call a professional experienced in furnace installation Frederick as soon as possible so they can take a look at your system and, if required, perform a furnace heat exchanger replacement. Costs should 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 regularly covered by the warranty. You’ll want to review the warranty paperwork on your furnace, as while the warranty won't always cover the entire cost of repairs, it can significantly reduce your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the most convenient ways to avoid problems in your furnace overall is with regular furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Contacting a skilled professional to check your furnace for broken-down parts, clogs in the air filters and other likely 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 connected to the heat exchanger itself, the strain of drawing air through a clogged filter makes your entire furnace work longer to complete its job. And the harder your furnace needs to run, the more strain pieces like the heat exchanger will sustain.