A furnace is usually a background player in your home, ensuring you're warm across the cold winter months. It often won't be noticed until a malfunction appears. 

One root cause could be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s important to know the symptoms of a cracked heat exchanger and what to do if you believe that might be the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps move heat from the combustion chamber in your furnace to the air that circulates through the ventilation. It generally does this through coils or tubes that warm the air while serving as a barrier to keep gas formed 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’s no surprise that a cracked heat exchanger can pose a risk. Cracks in the heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to be distributed throughout your home. 

For obvious reasons, never use your heating if you think there's a crack in the heat exchanger, as doing so could make the entire family ill. Call an HVAC professional as soon as possible if you are worried your heater has a cracked heat exchanger that needs to be repaired. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: A crack in your heat exchanger could cause your furnace to turn off. 
  • Odd Smells: If the air coming out of your furnace has an intense chemical smell, it could be evidence gas is slipping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm goes off or you notice health problems: If a cracked heat exchanger is releasing carbon monoxide inside your home, your carbon monoxide alarm may go off or family members could struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel sick, get out of the home immediately and then call for help. 
  • Soot: If you see black sooty buildup around the exterior of your furnace, it’s an indication something may be seriously wrong.

What You Can Do if Your Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, hire a professional with extensive experience in furnace installation Tucker as soon as possible 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 often hover around $1,000 to $3,000. 

However, the good news is that heat exchangers are often included in the warranty. You’ll want to check the warranty paperwork on your furnace, since while the warranty might not 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 via regular furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Hiring a skilled professional to check your furnace for broken-down parts, clogs in the air 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 encouraged some filters be changed every 90 days or sooner if they are dirty or grimy. While the filters aren't connected to the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work more vigorously to do its job. And the harder your furnace needs to run, the more deterioration components like the heat exchanger will sustain.