A furnace is almost always a background player at home, ensuring you're warm across the cold winter months. It often doesn’t get noticed until something breaks down. 

One root cause might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to learn the signs of a cracked heat exchanger and what you can do if you are worried that may be the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps move heat from the combustion chamber inside your furnace to the air that moves through the system. It generally accomplishes this via coils or tubes that heat up the air while functioning as a barrier to keep the gasses formed in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

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

For this reason, don't ever run your heating if you believe there's a crack in the heat exchanger, as this could make the entire family ill. Reach out to an HVAC professional as soon as possible if you believe your heating has a cracked heat exchanger that needs repair. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: A crack in your heat exchanger can cause your furnace to turn off. 
  • Odd Smells: If the air escaping your furnace has a strong chemical odor, it may be an indicator that gas is seeping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm initiates or you feel health problems: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm should go off or family members could struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unwell, get out of the home immediately and then call for help. 
  • Soot: If you spot 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 with extensive experience in furnace installation McKinney and Frisco right away so they can inspect your system and, if required, start a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

However, the good news is that heat exchangers are often included in the warranty. You should confirm the warranty paperwork on your furnace, since while the warranty may not cover the entire cost of repairs, it could significantly shrink your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the most convenient ways to avoid problems in your furnace overall is through routine furnace maintenance. Furnaces offer the most benefits when they run efficiently. Hiring a trained professional to inspect your furnace for old parts, clogged filters and other common problems can help you avoid getting a big bill later on.  

It’s also a good idea 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 your entire furnace work harder to accomplish its job. And the harder your furnace has to work, the more strain pieces like the heat exchanger will endure.