A furnace is almost always a background player for your home, helping keep you warm across the cold winter months. It frequently doesn’t get noticed until a malfunction appears. 

One source could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to learn the signs of a cracked heat exchanger and what to do if you are worried that may 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 circulates inside the ventilation. It usually handles this with coils or tubes that heat the air while serving as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from leaking out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its important role, it isn't surprising that a damaged heat exchanger can be very dangerous. A damaged heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to circulate across your home. 

For this reason, do NOT run your heating if you believe it has a cracked heat exchanger, as doing so could make your entire family sick. Reach out to an HVAC professional as soon as possible if you believe your furnace has a cracked heat exchanger that needs to be repaired. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: A cracked heat exchanger could cause your furnace to shut off. 
  • Odd Smells: If the air leaving your furnace has a powerful chemical scent, it may be evidence gasses are slipping 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 poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm should go off or family members might struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling tired. 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 notice black sooty buildup near the exterior of your furnace, it’s another sign something might be seriously wrong.

What You Should Do if Your Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, contact a professional well versed in furnace installation Buellton as soon as possible so they can examine your system and, if needed, start a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are generally covered by the warranty. It's a good idea to review the warranty paperwork on your furnace, since while the warranty might not cover the entire cost of repairs, it still may significantly shrink your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the most convenient ways to avoid problems in your furnace overall is via regular furnace maintenance. Furnaces offer the most benefits when they work efficiently. Hiring a trained professional to inspect your furnace for old parts, dirty filters and other likely problems can keep you from getting a big bill later on.  

It’s also a good idea to take a look at 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 are not part of the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work longer to accomplish its job. And the harder your furnace works, the more deterioration components like the heat exchanger will sustain.