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

September 20, 2022

A furnace is often a background player at home, keeping you warm across the cold winter months. It frequently doesn’t get noticed until something goes wrong.

One cause may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s critical to learn the symptoms 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 helps transition heat from the combustion chamber inside your furnace to the air that moves throughout the air ducts. It usually does this via coils or tubes that warm the air while serving as a barrier to keep gas created in the combustion chamber, called flue gasses, from escaping out into your home.

Is a Cracked Heat Exchanger Dangerous?

Given its central role, it isn't surprising that a broken heat exchanger can be hazardous. A crack in the heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home.

For this reason, don't ever run your furnace if you think there's a crack in the heat exchanger, as this could make the whole household ill. Contact an HVAC professional immediately if you are worried your heating has a cracked heat exchanger that needs to be repaired.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace turns off: A cracked heat exchanger could cause your furnace to turn off.
  • Unusual Smells: If the air coming out of your furnace has a strong chemical scent, it could be evidence gas is seeping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a major warning sign.
  • Carbon monoxide alarm goes off or you notice poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm should go off or household members could experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel unusually tired, get out of the home immediately and then call for help.
  • Soot: If you spot black sooty buildup around the exterior of your furnace, it’s another sign something may be seriously wrong.

What to Do if the Furnace Heat Exchanger is Cracked

If you believe your furnace has a cracked heat exchanger, call a pro with extensive experience in furnace installation Murrieta as soon as possible so they can examine your system and, if necessary, perform a furnace heat exchanger replacement. Costs often 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 protected by the warranty. It's a good idea to check the warranty paperwork on your furnace, since while the warranty may not cover the entire cost of repairs, it could significantly shrink 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 through consistent furnace maintenance. Furnaces work the best when they run efficiently. Hiring a trained professional to examine your furnace for broken-down parts, clogs in the air filters and other common problems can help you avoid 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 ideal 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 dragging air through a clogged filter makes the entire furnace work more vigorously to complete its job. And the harder your furnace has to work, the more wear and tear pieces like the heat exchanger will experience.