A furnace is usually a background player at home, helping keep you warm in the cold winter months. It regularly won't be noticed until something goes wrong. 

One source may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s important to learn the symptoms of a cracked heat exchanger and what you can do if you are worried that may be the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps transition heat from the combustion chamber in your furnace to the air that circulates inside the air ducts. It usually accomplishes 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 escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its key role, it shouldn't come as a surprise that a broken heat exchanger can be very dangerous. A crack in the heat exchanger can allow dangerous gasses – such as carbon monoxide, which can be lethal – to be distributed throughout your home. 

For that reason, don't ever turn on your heating if you believe there's a crack in the heat exchanger, as letting it run could make your entire household sick. Reach out to an HVAC professional immediately if you think your heater has a cracked heat exchanger that needs to be repaired. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace switches off: A cracked heat exchanger can cause your furnace to turn off. 
  • Odd Smells: If the air leaving your furnace has a powerful chemical scent, it may be an indicator that gasses are leaking 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 recognize poisoning symptoms: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm should go off or family members could experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel sick, leave the home right away and then call for help. 
  • Soot: If you spot black sooty accumulating around 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 worry your furnace has a cracked heat exchanger, contact a professional well versed in furnace installation Chelan and Wenatchee 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 run in the neighborhood of $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are generally covered by the warranty. You’ll want to review the warranty paperwork on your furnace, as while the warranty won't always cover the entire cost of repairs, it can significantly shrink your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the best ways to avoid problems in your furnace overall is through consistent furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Calling a skilled professional to inspect your furnace for old parts, clogged filters and other common problems can keep you from getting a big bill later on.  

It’s also a good idea to take a look at your furnace filters every few months – it’s recommended some filters be replaced 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 the entire furnace work more vigorously to do its job. And the harder your furnace works, the more strain components like the heat exchanger will endure.