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

One source might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to know the evidence of a cracked heat exchanger and what to do if you believe that may be 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 flows through the air ducts. It usually handles this through coils or tubes that heat the air while serving as a barrier to keep byproducts produced in the combustion chamber, called flue gasses, from escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its key role, it isn't surprising that a cracked heat exchanger can pose a risk. A crack in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to circulate through your home. 

For this reason, never use your heater if you suspect it has a cracked heat exchanger, as letting it run could make your entire family sick. Reach out to an HVAC professional as soon as possible if you believe your heater has a cracked heat exchanger that needs to be repaired. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: A cracked heat exchanger may cause your furnace to turn off. 
  • Odd Smells: If the air leaving your furnace has an intense chemical scent, it may be an indicator that gas is seeping through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm is triggered or you recognize symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide inside your home, your carbon monoxide alarm could go off or family members could experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel sick, exit the home as soon as you can and then call for help. 
  • Soot: If you spot black sooty accumulating near the exterior of your furnace, it’s an indication something could be seriously wrong.

What to Do if Your Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation Holdrege as soon as possible so they can inspect your system and, if needed, start a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates often hover around $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are often protected by the warranty. You’ll want to check the warranty paperwork on your furnace, since while the warranty may not 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 easiest ways to prevent a problem in your furnace overall is with consistent furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Contacting a trained professional to inspect your furnace for worn-out parts, clogged filters and other common problems can keep you from getting a big bill later on.  

It’s also beneficial to take a look at your furnace filters every few months – it’s recommended some filters be swapped out 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 pulling air through a clogged filter makes your entire furnace work more vigorously to accomplish its job. And the harder your furnace works, the more strain pieces like the heat exchanger will experience.