Cracked Heat Exchanger: What This Means and What You Should Do Next

September 20, 2022

A furnace is almost always a background player in your home, ensuring you're warm in the cold winter months. It regularly won't be noticed until something goes wrong.

One cause might be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s worthwhile to know the signs of a cracked heat exchanger and what to do if you are worried that might 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 circulates through the ventilation. It usually accomplishes this using coils or tubes that warm the air while acting as a barrier to keep the gasses created in the combustion chamber, called flue gasses, from getting out into your home.

Is a Cracked Heat Exchanger Dangerous?

Given its central role, it’s no surprise that a cracked heat exchanger can pose a risk. Cracks in the heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to flow throughout your home.

For that reason, do NOT use your furnace if you believe you're dealing with a cracked heat exchanger, as this could make your entire family ill. Reach out to an HVAC professional immediately if you believe your heating has a cracked heat exchanger that needs to be repaired.

Four Warning Signs of a Cracked Heat Exchanger:

  • Furnace shuts off: A cracked heat exchanger could cause your furnace to turn off.
  • Unusual Smells: If the air coming out of your furnace has an intense chemical odor, it could be a sign 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 recognize poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide inside your home, your carbon monoxide alarm should go off or family members could start experiencing signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unusually tired, leave the home immediately and then call for help.
  • Soot: If you spot black sooty buildup on the exterior of your furnace, it’s another sign something may be seriously wrong.

What to Do if a Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, hire a pro with extensive experience in furnace installation Savage as soon as possible so they can examine your system and, if needed, start 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 often 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 reduce your bill.

How to Avoid a Cracked Heat Exchanger in Your Home

One of the easiest ways to minimize the risk of problems in your furnace overall is with regular furnace maintenance. Furnaces work the best when they run efficiently. Hiring a certified professional to check your furnace for old parts, dirty filters and other common 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 changed 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 dragging air through a clogged filter makes your entire furnace work harder to complete its job. And the harder your furnace has to work, the more strain parts like the heat exchanger will sustain.