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 goes wrong. 

One root cause may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s important to learn the signs of a cracked heat exchanger and what you should do if you suspect that is the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps transition heat from the combustion chamber inside your furnace to the air that circulates through the air ducts. It typically accomplishes this via coils or tubes that heat up the air while functioning as a barrier to keep byproducts produced in the combustion chamber, called flue gasses, from leaking out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its central role, it’s no surprise that a broken heat exchanger can be hazardous. A crack in the heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to be distributed throughout your home. 

For that reason, don't ever run your heater if you suspect you're dealing with a cracked heat exchanger, as doing so could make the whole family sick. Call an HVAC professional as soon as possible if you believe your heating has a cracked heat exchanger that should be repaired. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace turns off: A cracked heat exchanger can cause your furnace to shut off. 
  • Odd Smells: If the air coming out of your furnace has a powerful chemical odor, it might be an indicator that gas is seeping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm initiates or you recognize symptoms of poisoning: If a cracked heat exchanger is relieving carbon monoxide inside your home, your carbon monoxide alarm should go off or family members might experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel sick, leave the home immediately and then call for help. 
  • Soot: If you spot black sooty accumulating near the exterior of your furnace, it’s more evidence something could be seriously wrong.

What You Can Do if a Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, call a pro well versed in furnace installation Belton as soon as possible so they can take a look at your system and, if necessary, handle a furnace heat exchanger replacement. Costs will differ depending on the situation, but estimates often hover around $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are often covered by the warranty. You’ll want to check the warranty paperwork on your furnace, because while the warranty won't always cover the entire cost of repairs, it can significantly lower your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the easiest ways to minimize the risk of problems in your furnace overall is through consistent furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Calling a skilled professional to inspect your furnace for old parts, dirty filters and other potential problems can keep you from getting a big bill later on.  

It’s also a good idea to inspect 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 dragging air through a clogged filter makes your entire furnace work harder to accomplish its job. And the harder your furnace works, the more deterioration pieces like the heat exchanger will sustain.