A furnace is often a background player at home, helping keep you warm during the cold winter months. It frequently isn't noticed until something goes wrong. 

One root cause may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to familiarize yourself with the evidence of a cracked heat exchanger and what you can do if you believe that might be 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 throughout the system. It generally does this through coils or tubes that heat the air while acting as a barrier to keep the gasses produced in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its important role, it’s no surprise that a broken heat exchanger can pose a risk. A damaged heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to flow throughout your home. 

For that reason, do NOT run your heating if you suspect there's a crack in the heat exchanger, as letting it run could make the entire family ill. Call an HVAC professional as soon as possible if you are worried your heating has a cracked heat exchanger that needs to be repaired. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: Cracks in the heat exchanger can cause your furnace to turn off. 
  • Unusual Smells: If the air leaving your furnace has a powerful chemical smell, it might be an indicator that gasses are slipping through cracks in your heat exchanger. These byproducts, which will often smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm initiates or you notice symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm may go off or family members could experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel unwell, get out of the home as soon as you can and then call for help. 
  • Soot: If you see black sooty buildup around the exterior of your furnace, it’s another sign something could be seriously wrong.

What You Can Do if Your Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, contact a professional experienced in furnace installation South Beloit and Belvidere right away so they can inspect your system and, if required, perform a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Fortunately, 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 may not cover the entire cost of repairs, it could significantly reduce 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 through consistent furnace maintenance. Furnaces provide the best possible return on investment when they run efficiently. Hiring a trained professional to check your furnace for worn-out parts, dirty filters and other common problems can help you avoid getting a big bill later on.  

It’s also a good idea to review your furnace filters every few months – it’s encouraged some filters be swapped out 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 more vigorously to accomplish its job. And the harder your furnace works, the more wear and tear pieces like the heat exchanger will experience.