A furnace is often a background player in your home, ensuring you're warm across the cold winter months. It frequently doesn’t get noticed until a malfunction appears. 

One cause could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to learn the symptoms of a cracked heat exchanger and what to 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 in your furnace to the air that circulates throughout the air ducts. It usually handles this through coils or tubes that heat the air while serving as a barrier to keep gas produced in the combustion chamber, called flue gasses, from getting out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its important role, it isn't surprising that a broken heat exchanger can be hazardous. A damaged heat exchanger can enable dangerous gasses – such as carbon monoxide, which can be lethal – to flow throughout your home. 

For this reason, do NOT turn on your heater if you think there's a crack in the heat exchanger, as doing so could make the entire family sick. Contact an HVAC professional right away if you believe your heater has a cracked heat exchanger that should be repaired. 

Four Warning 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 escaping your furnace has a strong chemical odor, it might be an indicator that gasses are seeping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm could go off or family members might struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unwell, leave the home as soon as you can and then call for help. 
  • Soot: If you notice black sooty collecting near the exterior of your furnace, it’s an indication something might be seriously wrong.

What You Can Do if Your Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation Highlands Ranch as soon as possible so they can examine your system and, if necessary, start a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates often hover around $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are generally protected by the warranty. You should confirm the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it still may significantly lower 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 through routine furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Hiring a skilled professional to examine your furnace for broken-down parts, clogs in the air filters and other likely problems can keep you from getting a big bill later on.  

It’s also beneficial 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 aren't a part of the heat exchanger itself, the strain of pulling air through a clogged filter makes your entire furnace work more vigorously to do its job. And the harder your furnace works, the more deterioration components like the heat exchanger will endure.