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

September 20, 2022

A furnace is often a background player at home, keeping you warm during the cold winter months. It regularly doesn’t get noticed until something breaks down.

One source might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s important to know the signs of a cracked heat exchanger and what you should 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 circulates through the system. It typically handles this with coils or tubes that warm the air while acting as a barrier to keep the gasses produced in the combustion chamber, called flue gasses, from leaking out into your home.

Is a Cracked Heat Exchanger Dangerous?

Thanks to its key role, it isn't surprising that a broken heat exchanger can pose a risk. A damaged heat exchanger can enable dangerous gasses – such as carbon monoxide, which can be lethal – to circulate through your home.

For obvious reasons, don't ever turn on your furnace if you suspect you're dealing with a cracked heat exchanger, as this could make the entire household ill. Reach out to an HVAC professional as soon as possible if you are worried your heating has a cracked heat exchanger that needs to be repaired.

Four Signs of a Cracked Heat Exchanger:

  • Furnace switches off: A crack in your heat exchanger could cause your furnace to switch off.
  • Strange Smells: If the air leaving your furnace has a strong chemical odor, it might be evidence gasses are leaking through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm initiates or you recognize health problems: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm should go off or family members might struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If the 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 notice black sooty buildup on the exterior of your furnace, it’s an indication something might be seriously wrong.

What to Do if Your Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, call a professional with extensive experience in furnace installation Rapid City right away so they can examine your system and, if required, start a furnace heat exchanger replacement. Costs often fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000.

Estimates aside, the good news is that heat exchangers are generally covered by the warranty. You’ll want to confirm the warranty paperwork on your furnace, because while the warranty may not cover the entire cost of repairs, it can significantly reduce 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 through routine furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Hiring a trained professional to examine your furnace for broken-down parts, dirty filters and other potential problems can help you avoid getting a big bill later on.

It’s also helpful to review your furnace filters every few months – it’s recommended some filters be swapped out 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 drawing 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 parts like the heat exchanger will endure.