Cracked Heat Exchanger: What That Means and What to Do Next

September 20, 2022

A furnace is almost always a background player in your home, ensuring you're warm across the cold winter months. It regularly doesn’t get noticed until something breaks down.

One source may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s critical to familiarize yourself with the signs 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 move heat from the combustion chamber inside your furnace to the air that circulates throughout the system. It usually handles this with coils or tubes that heat 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 important role, it shouldn't come as a surprise that a damaged heat exchanger can pose a risk. A crack in the heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to be distributed through your home.

For this reason, do NOT run your heater if you suspect you're dealing with a cracked heat exchanger, as letting it run could make the entire family ill. Contact an HVAC professional right away if you believe your furnace has a cracked heat exchanger that needs repair.

Four Signs of a Cracked Heat Exchanger:

  • Furnace turns off: A crack in your heat exchanger may cause your furnace to shut off.
  • Strange Smells: If the air escaping your furnace has a powerful chemical smell, it may be evidence gasses are leaking through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a common warning sign.
  • Carbon monoxide alarm is triggered or you feel poisoning symptoms: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm may go off or family members might experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If your alarm goes off or you feel unusually tired, exit the home immediately and then call for help.
  • Soot: If you notice black sooty collecting near the exterior of your furnace, it’s another sign something may be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, contact a pro well versed in furnace installation Rapid City as soon as possible so they can inspect your system and, if needed, perform a furnace heat exchanger replacement. Costs will differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000.

Estimates aside, the good news is that heat exchangers are regularly covered by the warranty. It's a good idea to review the warranty paperwork on your furnace, since while the warranty may not cover the entire cost of repairs, it could significantly lower your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the best 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 run efficiently. Hiring a trained professional to check your furnace for worn-out parts, dirty filters and other common problems can help you avoid getting a big bill later on.

It’s also helpful to take a look at your furnace filters every few months – it’s ideal 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 accomplish its job. And the harder your furnace works, the more deterioration pieces like the heat exchanger will sustain.