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

September 20, 2022

A furnace is often a background player at home, keeping you warm during the cold winter months. It often isn't noticed until a malfunction appears.

One root cause could be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to know the signs of a cracked heat exchanger and what you can do if you suspect that may 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 circulates throughout the ventilation. It typically accomplishes this using coils or tubes that heat up the air while functioning as a barrier to keep gas formed in the combustion chamber, called flue gasses, from escaping out into your home.

Is a Cracked Heat Exchanger Dangerous?

Because of its central role, it isn't surprising that a broken heat exchanger can pose a risk. Cracks in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home.

For this reason, do NOT run your furnace if you believe there's a crack in the heat exchanger, as this could make your entire household sick. Call an HVAC professional immediately if you are worried your furnace has a cracked heat exchanger that should be repaired.

Four Signs of a Cracked Heat Exchanger:

  • Furnace switches off: A crack in your heat exchanger may cause your furnace to switch off.
  • Unusual Smells: If the air escaping your furnace has an intense chemical smell, it might be a sign gasses are seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm may go off or household members could start experiencing signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel sick, get out of the home right away and then call for help.
  • Soot: If you notice black sooty collecting around the exterior of your furnace, it’s an indication something might be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, hire a professional with extensive experience in furnace installation Mobile right away so they can examine your system and, if needed, start a furnace heat exchanger replacement. Costs often vary depending on the situation, but estimates often hover around $1,000 to $3,000.

However, the good news is that heat exchangers are regularly protected by the warranty. You should confirm the warranty paperwork on your furnace, since while the warranty might not cover the entire cost of repairs, it can significantly lower your bill.

How to Avoid a Cracked Heat Exchanger in Your Home

One of the best ways to prevent a problem in your furnace overall is through consistent furnace maintenance. Furnaces offer the most benefits when they run efficiently. Contacting a certified professional to examine your furnace for old parts, clogs in the air filters and other potential problems can keep you from getting a big bill later on.

It’s also a good idea to review your furnace filters every few months – it’s recommended some filters be replaced 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 the entire furnace work longer to accomplish its job. And the harder your furnace needs to run, the more strain pieces like the heat exchanger will endure.