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

One cause may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s important to know the symptoms of a cracked heat exchanger and what you should do if you are worried 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 circulates through the ventilation. It usually accomplishes this using coils or tubes that heat the air while serving as a barrier to keep the gasses produced in the combustion chamber, called flue gasses, from escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its key role, it’s no surprise that a damaged heat exchanger can pose a risk. Cracks in the heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to circulate through your home. 

For obvious reasons, never turn on your furnace if you believe it has a cracked heat exchanger, as letting it run could make the entire household ill. Call an HVAC professional as soon as possible if you think your heating has a cracked heat exchanger that needs to be repaired. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace turns off: A crack in your heat exchanger can cause your furnace to switch off. 
  • Unusual Smells: If the air escaping your furnace has a strong chemical odor, it may be an indicator that gasses are slipping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm initiates or you notice health problems: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm could go off or family members could start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If your alarm goes off or you feel sick, get out of the home right away and then call for help. 
  • Soot: If you see black sooty collecting on the exterior of your furnace, it’s another sign something may 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 pro experienced in furnace installation Arlington right away so they can take a look at your system and, if necessary, 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 generally included in the warranty. It's a good idea to review the warranty paperwork on your furnace, as while the warranty may not cover the entire cost of repairs, it can significantly reduce 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 regular furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Hiring a skilled professional to inspect your furnace for broken-down 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 encouraged some filters be swapped out 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 harder to do its job. And the harder your furnace needs to run, the more deterioration components like the heat exchanger will sustain.