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

One source may 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 should 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 moves through the ventilation. It usually handles this via coils or tubes that heat the air while functioning 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? 

Given its important role, it’s no surprise that a damaged heat exchanger can be very dangerous. Cracks in the heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to flow throughout your home. 

For this reason, never turn on your heating if you suspect there's a crack in the heat exchanger, as doing so could make the whole family ill. Call an HVAC professional as soon as possible if you are worried your furnace has a cracked heat exchanger that needs repair. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace switches off: A crack in your heat exchanger may cause your furnace to switch off. 
  • Strange Smells: If the air escaping your furnace has an intense chemical odor, it could be an indicator that gasses are leaking through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm is triggered or you recognize poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide into your home, your carbon monoxide alarm should go off or household members may start experiencing signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel unusually tired, leave the home right away and then call for help. 
  • Soot: If you find black sooty accumulating around the exterior of your furnace, it’s an indication something might be seriously wrong.

What You Can Do if the Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, call a professional well versed in furnace installation Des Moines right away so they can inspect your system and, if needed, perform a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are often covered by the warranty. You should check the warranty paperwork on your furnace, as while the warranty won't always cover the entire cost of repairs, it still may 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 through routine furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Hiring a skilled professional to check your furnace for worn-out parts, dirty filters and other potential problems can help you avoid getting a big bill later on.  

It’s also beneficial to inspect 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 aren't connected to the heat exchanger itself, the strain of pulling 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 wear and tear components like the heat exchanger will endure.