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

September 20, 2022

A furnace is often a background player for your home, keeping you warm across the cold winter months. It regularly doesn’t get noticed until a malfunction appears.

One root cause might 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 are worried that might be the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger transfers heat from the combustion chamber of your furnace to the air that flows throughout the air ducts. It generally accomplishes 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 escaping out into your home.

Is a Cracked Heat Exchanger Dangerous?

Given its important role, it’s no surprise that a cracked heat exchanger can be very dangerous. A damaged heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to be distributed across your home.

For this reason, never run your furnace if you think there's a crack in the heat exchanger, as letting it run could make your entire family ill. Contact an HVAC professional right away if you are worried your furnace has a cracked heat exchanger that should be repaired.

Four Warning Signs of a Cracked Heat Exchanger:

  • Furnace turns 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 may be an indicator that gas is leaking through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a common warning sign.
  • Carbon monoxide alarm is triggered or you notice symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm may go off or family members could start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unwell, get out of the home right away and then call for help.
  • Soot: If you see black sooty collecting on the exterior of your furnace, it’s more evidence something might be seriously wrong.

What You Can Do if a Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, hire a professional with extensive experience in furnace installation Anchorage as soon as possible so they can inspect your system and, if needed, handle a furnace heat exchanger replacement. Costs often vary 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 protected by the warranty. You should review the warranty paperwork on your furnace, as while the warranty won't always cover the entire cost of repairs, it can significantly reduce your bill.

How to Avoid a Cracked Heat Exchanger in Your Home

One of the most convenient ways to prevent a problem in your furnace overall is through consistent furnace maintenance. Furnaces offer the most benefits when they run efficiently. Calling a skilled professional to inspect 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 beneficial to inspect 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 a part of the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work longer to do its job. And the harder your furnace works, the more deterioration pieces like the heat exchanger will experience.