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

One source might be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to learn the symptoms of a cracked heat exchanger and what to do if you believe that might be the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps move heat from the combustion chamber of your furnace to the air that moves inside the ventilation. It typically does this via coils or tubes that warm 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? 

Given its important role, it shouldn’t come as a surprise that a cracked heat exchanger can be very dangerous. Cracks in the heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to flow through your home. 

For obvious reasons, do NOT use your heater if you believe there’s a crack in the heat exchanger, as letting it run could make the entire household ill. Contact an HVAC professional right away if you are worried your furnace has a cracked heat exchanger that should be repaired. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace switches off: A cracked heat exchanger can cause your furnace to switch off. 
  • Unusual Smells: If the air leaving your furnace has a powerful chemical scent, it may be a sign gasses are seeping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm is triggered or you feel health problems: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm may go off or household members might experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If the alarm goes off or you feel unwell, leave the home right away and then call for help. 
  • Soot: If you find black sooty buildup 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 worry your furnace has a cracked heat exchanger, call a professional experienced in furnace installation McAllen as soon as possible so they can inspect your system and, if required, start a furnace heat exchanger replacement. Costs often differ depending on the situation, but estimates often hover around $1,000 to $3,000. 

However, the good news is that heat exchangers are often covered by the warranty. You’ll want to review the warranty paperwork on your furnace, since while the warranty might not cover the entire cost of repairs, it can significantly shrink your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the most convenient ways to minimize the risk of problems in your furnace overall is via regular furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Hiring a trained professional to examine your furnace for old parts, dirty 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 encouraged 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 your entire furnace work longer to complete its job. And the harder your furnace needs to run, the more deterioration pieces like the heat exchanger will experience.