A furnace is usually a background player in your home, helping keep you warm during the cold winter months. It often 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 familiarize yourself with the signs 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 helps transition heat from the combustion chamber of your furnace to the air that circulates through the ventilation. It generally accomplishes this through coils or tubes that heat the air while functioning as a barrier to keep gas formed in the combustion chamber, called flue gasses, from escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its central role, it’s no surprise that a cracked heat exchanger can pose a risk. A damaged heat exchanger can enable dangerous gasses – such as carbon monoxide, which can be lethal – to flow across your home. 

For that reason, do NOT use your heating if you believe you're dealing with a cracked heat exchanger, as doing so could make your entire family ill. Reach out to an HVAC professional as soon as possible if you believe your furnace has a cracked heat exchanger that needs to be repaired. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger could cause your furnace to switch off. 
  • Unusual Smells: If the air leaving your furnace has an intense chemical odor, it could be a sign gas is slipping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm initiates or you feel health problems: If a cracked heat exchanger is relieving carbon monoxide inside your home, your carbon monoxide alarm may go off or household members may struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel unusually tired, exit the home immediately and then call for help. 
  • Soot: If you spot black sooty accumulating around the exterior of your furnace, it’s another sign something may be seriously wrong.

What to Do if Your Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, call a pro with extensive experience in furnace installation Safford as soon as possible so they can take a look at your system and, if needed, perform a furnace heat exchanger replacement. Costs should vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are generally protected by the warranty. You should check the warranty paperwork on your furnace, as while the warranty may not cover the entire cost of repairs, it can significantly reduce your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the easiest ways to avoid problems in your furnace overall is through routine furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Contacting a skilled professional to check your furnace for old parts, clogged filters and other potential problems can keep you from getting a big bill later on.  

It’s also beneficial to review 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 connected to the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work harder to do its job. And the harder your furnace needs to run, the more deterioration parts like the heat exchanger will experience.