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

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

What Is a Heat Exchanger in a Furnace? 

A heat exchanger transfers heat from the combustion chamber in your furnace to the air that circulates inside the air ducts. It typically handles this using coils or tubes that heat up the air while functioning 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 broken heat exchanger can pose a risk. A damaged heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to circulate throughout your home. 

For obvious reasons, do NOT turn on your heater if you believe there's a crack in the heat exchanger, as letting it run could make the entire family ill. Call an HVAC professional as soon as possible if you think your heater has a cracked heat exchanger that needs to be repaired. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: Cracks in the heat exchanger may cause your furnace to shut off. 
  • Strange Smells: If the air leaving your furnace has an intense chemical scent, it might be an indicator that gas is leaking through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm is triggered or you recognize symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm could go off or family members could experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an alarm goes off or you feel sick, leave the home as soon as you can and then call for help. 
  • Soot: If you spot black sooty collecting on 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 believe your furnace has a cracked heat exchanger, contact a professional well versed in furnace installation Macon as soon as possible so they can take a look at your system and, if needed, perform a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are generally protected by the warranty. You should confirm the warranty paperwork on your furnace, as while the warranty may not 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 best ways to minimize the risk of problems in your furnace overall is through routine furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Calling a trained 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 connected to the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work longer to complete its job. And the harder your furnace has to work, the more wear and tear components like the heat exchanger will endure.