A furnace is almost always a background player at home, keeping 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 be a safety risk, so it’s critical to learn 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 helps transition heat from the combustion chamber inside your furnace to the air that flows inside the ventilation. It typically does this via coils or tubes that warm the air while acting as a barrier to keep the gasses formed 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 cracked heat exchanger can be hazardous. Cracks in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to be distributed throughout your home. 

For that reason, don't ever use your furnace if you suspect you're dealing with a cracked heat exchanger, as letting it run could make the whole family ill. Call an HVAC professional right away if you are worried your heater has a cracked heat exchanger that needs repair. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger can cause your furnace to turn off. 
  • Strange Smells: If the air coming out of your furnace has a powerful chemical odor, it may be a sign gas is leaking through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm goes off or you feel poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm may go off or household members might experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If your alarm goes off or you feel unwell, exit the home right away and then call for help. 
  • Soot: If you see black sooty accumulating on the exterior of your furnace, it’s more evidence something might be seriously wrong.

What to Do if Your Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, contact a pro well versed in furnace installation Highlands Ranch as soon as possible so they can take a look at your system and, if necessary, perform a furnace heat exchanger replacement. Costs often differ depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are regularly included in the warranty. It's a good idea to review the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it can significantly shrink your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the best ways to avoid problems in your furnace overall is through routine furnace maintenance. Furnaces work the best when they work efficiently. Calling a skilled professional to inspect your furnace for worn-out parts, clogs in the air filters and other likely 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 ideal 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 drawing air through a clogged filter makes your entire furnace work longer to do its job. And the harder your furnace needs to run, the more wear and tear components like the heat exchanger will sustain.