A furnace is often a background player in your home, keeping you warm during the cold winter months. It often doesn’t get noticed until a malfunction appears. 

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

What Is a Heat Exchanger in a Furnace? 

A heat exchanger transfers heat from the combustion chamber of your furnace to the air that flows throughout the system. It typically does this using coils or tubes that warm the air while functioning as a barrier to keep gas created 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 damaged heat exchanger can pose a risk. Cracks in the heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to circulate across your home. 

For obvious reasons, never turn on your heating if you think you're dealing with a cracked heat exchanger, as doing so could make your entire household ill. Call an HVAC professional as soon as possible if you believe your heater has a cracked heat exchanger that needs repair. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: A cracked heat exchanger could cause your furnace to turn off. 
  • Unusual Smells: If the air leaving your furnace has a strong chemical scent, it may be evidence gas is leaking through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm may go off or family members might experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unwell, exit the home right away and then call for help. 
  • Soot: If you see black sooty accumulating around the exterior of your furnace, it’s an indication 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, contact a professional with extensive experience in furnace installation Mount Pleasant right away so they can examine your system and, if necessary, handle a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are regularly protected by the warranty. It's a good idea to check the warranty paperwork on your furnace, as while the warranty won't always cover the entire cost of repairs, it still may significantly shrink your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the best ways to minimize the risk of problems in your furnace overall is via routine furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Hiring a certified professional to examine your furnace for worn-out parts, dirty filters and other likely problems can keep you from 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 are not part of the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work longer to complete its job. And the harder your furnace needs to run, the more wear and tear parts like the heat exchanger will sustain.