A furnace is usually a background player in your home, helping keep you warm across the cold winter months. It often doesn’t get noticed until something breaks down. 

One source might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to know the symptoms of a cracked heat exchanger and what to do if you believe that may be 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 typically accomplishes this using coils or tubes that heat the air while acting as a barrier to keep the gasses formed in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Given its important role, it’s no surprise that a cracked heat exchanger can pose a risk. Cracks in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to circulate across your home. 

For that reason, never run your heater if you suspect there's a crack in the heat exchanger, as doing so could make the entire household ill. Reach out to an HVAC professional right away if you believe your heating has a cracked heat exchanger that needs repair. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace turns off: A crack in your heat exchanger can cause your furnace to shut off. 
  • Odd Smells: If the air leaving your furnace has a powerful chemical scent, it could be an indicator that gas is leaking through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm initiates or you feel poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm could go off or household members may struggle with signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an alarm goes off or you feel unwell, get out of the home immediately and then call for help. 
  • Soot: If you spot black sooty collecting around the exterior of your furnace, it’s more evidence something may 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 Huntingburg as soon as possible so they can examine your system and, if required, perform a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates often hover around $1,000 to $3,000. 

However, the good news is that heat exchangers are generally protected by the warranty. It's a good idea to review the warranty paperwork on your furnace, as while the warranty might not cover the entire cost of repairs, it can significantly lower your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the best ways to avoid problems in your furnace overall is via routine furnace maintenance. Furnaces offer the most benefits when they run efficiently. Hiring a certified professional to check your furnace for worn-out parts, clogs in the air filters and other common 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 recommended 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 more vigorously to complete its job. And the harder your furnace works, the more deterioration components like the heat exchanger will experience.