Cracked Heat Exchanger: What That Means and What You can Do Next

September 20, 2022

A furnace is almost always a background player in your home, helping keep you warm across the cold winter months. It frequently isn't noticed until something goes wrong.

One cause could be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s critical to familiarize yourself with the evidence of a cracked heat exchanger and what you can do if you suspect that might be the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger transfers heat from the combustion chamber in your furnace to the air that flows through the air ducts. It generally accomplishes this using coils or tubes that heat up the air while acting 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?

Because of its central role, it’s no surprise that a broken heat exchanger can be very dangerous. A crack in the heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to circulate throughout your home.

For obvious reasons, never use your heating if you think it has a cracked heat exchanger, as doing so could make the entire family sick. Call an HVAC professional as soon as possible if you think your heater has a cracked heat exchanger that should be repaired.

Four Warning Signs of a Cracked Heat Exchanger:

  • Furnace switches off: A cracked heat exchanger could cause your furnace to switch off.
  • Strange Smells: If the air coming out of your furnace has an intense chemical scent, it might be evidence gas is seeping through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a common warning sign.
  • Carbon monoxide alarm is triggered or you recognize symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm could go off or family members may experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel sick, get out of the home as soon as you can and then call for help.
  • Soot: If you see black sooty collecting around the exterior of your furnace, it’s another sign something may be seriously wrong.

What You Can Do if the Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, hire a pro well versed in furnace installation Muldrow right away so they can inspect your system and, if necessary, perform a furnace heat exchanger replacement. Costs often vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.

However, the good news is that heat exchangers are regularly covered by the warranty. It's a good idea to check the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it can significantly shrink your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the most convenient ways to avoid problems in your furnace overall is via regular furnace maintenance. Furnaces work the best when they run efficiently. Hiring a skilled professional to check your furnace for old parts, clogs in the air filters and other potential problems can help you avoid getting a big bill later on.

It’s also a good idea to review your furnace filters every few months – it’s encouraged some filters be replaced 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 more vigorously to do its job. And the harder your furnace needs to run, the more strain parts like the heat exchanger will sustain.