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

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

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps move heat from the combustion chamber of your furnace to the air that flows throughout the system. It generally handles this through coils or tubes that warm the air while acting as a barrier to keep byproducts formed in the combustion chamber, called flue gasses, from escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Given its central role, it isn't surprising that a damaged heat exchanger can be hazardous. A crack in the heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to flow throughout your home. 

For that reason, don't ever turn on your furnace if you believe it has a cracked heat exchanger, as letting it run could make the entire family sick. Contact an HVAC professional immediately if you are worried your heating has a cracked heat exchanger that should be repaired. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: A cracked heat exchanger could cause your furnace to shut off. 
  • Strange Smells: If the air leaving your furnace has a strong chemical smell, it may be evidence gasses are leaking through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm initiates or you notice symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm may go off or family members could struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If your alarm goes off or you feel sick, exit the home immediately and then call for help. 
  • Soot: If you notice black sooty collecting around the exterior of your furnace, it’s more evidence something may be seriously wrong.

What You Should Do if the Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, contact a pro well versed in furnace installation Arlington right away so they can take a look at your system and, if required, start a furnace heat exchanger replacement. Costs should vary 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. You should confirm the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it could significantly shrink your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the easiest ways to minimize the risk of problems in your furnace overall is via consistent furnace maintenance. Furnaces offer the most benefits when they work efficiently. Calling a skilled professional to check your furnace for broken-down parts, clogged filters and other potential 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 pulling air through a clogged filter makes your entire furnace work more vigorously to accomplish its job. And the harder your furnace needs to run, the more deterioration pieces like the heat exchanger will experience.