A furnace is often a background player in your home, keeping you warm during the cold winter months. It frequently won't be noticed until something breaks down. 

One cause may be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s worthwhile to learn the symptoms of a cracked heat exchanger and what to do if you are worried that is the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps transition heat from the combustion chamber inside your furnace to the air that circulates throughout the air ducts. It usually handles this through coils or tubes that warm the air while serving as a barrier to keep byproducts produced in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Given its central role, it’s no surprise that a damaged heat exchanger can pose a risk. A damaged heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home. 

For this reason, do NOT run your heating if you suspect it has a cracked heat exchanger, as this could make the whole family sick. Contact an HVAC professional as soon as possible if you think 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 can cause your furnace to shut off. 
  • Odd Smells: If the air coming out of your furnace has a strong chemical scent, it might be a sign gasses are leaking through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm initiates or you notice health problems: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm may go off or family members could start experiencing signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel unusually tired, get out of the home right away and then call for help. 
  • Soot: If you find black sooty collecting around the exterior of your furnace, it’s more evidence something may be seriously wrong.

What You Can 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 Zelienople right away so they can examine your system and, if necessary, perform a furnace heat exchanger replacement. Costs will differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are generally covered 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 still may 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 consistent furnace maintenance. Furnaces provide the best possible return on investment when they run efficiently. Hiring a certified professional to check 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 beneficial 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 drawing air through a clogged filter makes the entire furnace work more vigorously to accomplish its job. And the harder your furnace has to work, the more wear and tear parts like the heat exchanger will experience.