A furnace is often a background player for your home, ensuring you're warm across the cold winter months. It often won't be noticed until something goes wrong. 

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 inside your furnace to the air that moves throughout the ventilation. It typically accomplishes this via coils or tubes that heat the air while acting as a barrier to keep the gasses formed in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Given its important role, it isn't surprising that a damaged heat exchanger can be very dangerous. Cracks in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to flow through your home. 

For obvious reasons, don't ever run your heating if you suspect you're dealing with a cracked heat exchanger, as this could make the whole household sick. Reach out to an HVAC professional right away if you are worried your furnace has a cracked heat exchanger that needs repair. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: A cracked heat exchanger may cause your furnace to switch 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 gasses, which can smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm should go off or household members could experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel unwell, exit the home as soon as you can and then call for help. 
  • Soot: If you notice black sooty accumulating on the exterior of your furnace, it’s more evidence something might be seriously wrong.

What You Can Do if Your Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, call a professional with extensive experience in furnace installation Port St. Lucie as soon as possible so they can examine your system and, if required, start a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are regularly included in the warranty. It's a good idea to check the warranty paperwork on your furnace, because while the warranty won't always cover the entire cost of repairs, it still may significantly reduce your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the best ways to prevent a problem in your furnace overall is through regular furnace maintenance. Furnaces work the best when they operate efficiently. Contacting a certified professional to inspect your furnace for broken-down parts, clogs in the air filters and other common problems can help you avoid getting a big bill later on.  

It’s also beneficial 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 aren't connected to the heat exchanger itself, the strain of dragging 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 wear and tear pieces like the heat exchanger will experience.