A furnace is almost always a background player at home, ensuring you're warm during the cold winter months. It regularly won't be noticed until a malfunction appears. 

One source might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to familiarize yourself with the evidence of a cracked heat exchanger and what you can do if you suspect that may be 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 through the system. It usually does this with coils or tubes that heat up the air while serving as a barrier to keep gas created in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its central role, it isn't surprising that a damaged heat exchanger can pose a risk. A crack in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to circulate throughout your home. 

For this reason, don't ever run your heating if you believe you're dealing with a cracked heat exchanger, as letting it run could make the whole family sick. Contact an HVAC professional immediately if you are worried your heating has a cracked heat exchanger that needs repair. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger can cause your furnace to shut off. 
  • Odd Smells: If the air coming out of your furnace has a powerful chemical scent, it might be evidence gasses are seeping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm initiates or you recognize health problems: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm may go off or family members could struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel unusually tired, leave the home immediately and then call for help. 
  • Soot: If you find black sooty buildup near the exterior of your furnace, it’s another sign something might be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation Winnipeg as soon as possible so they can inspect your system and, if necessary, 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. 

Estimates aside, the good news is that heat exchangers are regularly protected 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 can significantly lower your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the most convenient ways to minimize the risk of problems in your furnace overall is with consistent furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Hiring a trained professional to check your furnace for old parts, clogs in the air 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 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 deterioration pieces like the heat exchanger will sustain.