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

One root cause might be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s important to know the evidence of a cracked heat exchanger and what you should do if you are worried that is the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger transfers heat from the combustion chamber inside your furnace to the air that circulates inside the air ducts. It usually handles this via coils or tubes that warm the air while functioning as a barrier to keep gas created in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its key role, it shouldn't come as a surprise that a damaged heat exchanger can be hazardous. A crack in the heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home. 

For this reason, don't ever run your furnace if you believe it has a cracked heat exchanger, as this could make the entire household ill. Reach out to an HVAC professional immediately if you believe your heater has a cracked heat exchanger that needs repair. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace shuts off: Cracks in the heat exchanger may cause your furnace to switch off. 
  • Odd Smells: If the air escaping your furnace has an intense chemical scent, it might be evidence gas is leaking through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm initiates or you recognize symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm should go off or family members could struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an alarm goes off or you feel unwell, leave the home right away and then call for help. 
  • Soot: If you see black sooty accumulating near the exterior of your furnace, it’s another sign something could be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, hire a pro experienced in furnace installation Thedford as soon as possible so they can inspect your system and, if necessary, handle a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are regularly covered by the warranty. It's a good idea to review the warranty paperwork on your furnace, because 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 easiest ways to prevent a problem in your furnace overall is through routine furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Hiring a trained professional to check your furnace for worn-out parts, clogs in the air filters and other common problems can help you avoid getting a big bill later on.  

It’s also helpful to inspect your furnace filters every few months – it’s ideal some filters be changed 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 pulling air through a clogged filter makes your entire furnace work longer to accomplish its job. And the harder your furnace works, the more strain pieces like the heat exchanger will endure.