A furnace is almost always a background player for your home, keeping you warm across the cold winter months. It often doesn’t get noticed until something goes wrong. 

One source might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s critical to learn the evidence of a cracked heat exchanger and what you should do if you suspect 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 flows throughout the ventilation. It typically handles this with coils or tubes that heat the air while serving 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? 

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

For this reason, do NOT run your heating if you suspect you're dealing with a cracked heat exchanger, as doing so could make the entire family ill. Call an HVAC professional immediately if you think your heater has a cracked heat exchanger that needs to be repaired. 

Four Symptoms of a Cracked Heat Exchanger: 

  • Furnace turns off: A cracked heat exchanger can cause your furnace to shut off. 
  • Odd Smells: If the air coming out of your furnace has an intense chemical odor, it might be a sign gas is seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is emitting carbon monoxide inside your home, your carbon monoxide alarm may go off or household members may start experiencing signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel unusually tired, get out of the home right away and then call for help. 
  • Soot: If you see black sooty accumulating near the exterior of your furnace, it’s another sign something might be seriously wrong.

What You Can Do if the Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, contact a pro well versed in furnace installation Dundas and Northfield right away so they can inspect your system and, if required, handle a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are generally included in the warranty. You should confirm the warranty paperwork on your furnace, because 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 easiest ways to avoid problems in your furnace overall is with 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 common problems can keep you from getting a big bill later on.  

It’s also helpful to review your furnace filters every few months – it’s encouraged 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 dragging air through a clogged filter makes your entire furnace work harder to do its job. And the harder your furnace has to work, the more strain components like the heat exchanger will sustain.