A furnace is almost always a background player at home, keeping you warm across the cold winter months. It frequently isn't noticed until a malfunction appears. 

One cause might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to learn the evidence of a cracked heat exchanger and what to 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 in your furnace to the air that circulates throughout the air ducts. It generally does this via coils or tubes that warm the air while serving as a barrier to keep the gasses produced in the combustion chamber, called flue gasses, from leaking out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Given its central role, it’s no surprise that a damaged heat exchanger can pose a risk. A crack in the heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to circulate through your home. 

For this reason, do NOT use your heating if you think it has a cracked heat exchanger, as letting it run could make the whole family sick. Call an HVAC professional as soon as possible if you think your heater has a cracked heat exchanger that needs to be repaired. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: A crack in your heat exchanger may cause your furnace to shut off. 
  • Odd Smells: If the air leaving your furnace has a powerful chemical scent, it could be an indicator that gas is slipping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm initiates or you notice poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide into your home, your carbon monoxide alarm could go off or family members might start experiencing signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If your alarm goes off or you feel unwell, exit the home immediately and then call for help. 
  • Soot: If you spot black sooty buildup around the exterior of your furnace, it’s an indication something might be seriously wrong.

What to Do if the Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, contact a professional well versed in furnace installation Circleville as soon as possible so they can examine your system and, if required, perform a furnace heat exchanger replacement. Costs should vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000. 

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

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the easiest ways to avoid problems in your furnace overall is through consistent furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Hiring a skilled professional to examine your furnace for old parts, dirty filters and other likely problems can help you avoid getting a big bill later on.  

It’s also helpful to inspect your furnace filters every few months – it’s ideal some filters be changed 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 longer to do its job. And the harder your furnace works, the more deterioration pieces like the heat exchanger will endure.