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

September 20, 2022

A furnace is often a background player for your home, helping keep 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’s a potentially dangerous issue, so it’s worthwhile to know the signs of a cracked heat exchanger and what you should do if you believe that may be the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger helps transition heat from the combustion chamber of your furnace to the air that circulates through the ventilation. It generally accomplishes this via coils or tubes that warm the air while serving as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from escaping out into your home.

Is a Cracked Heat Exchanger Dangerous?

Because of its important role, it isn't surprising that a damaged heat exchanger can be hazardous. A damaged heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to be distributed through your home.

For this reason, don't ever turn on your furnace if you suspect it has a cracked heat exchanger, as this could make your entire household ill. Reach out to an HVAC professional as soon as possible if you believe your furnace has a cracked heat exchanger that should be repaired.

Four Signs of a Cracked Heat Exchanger:

  • Furnace turns off: Cracks in the heat exchanger may cause your furnace to switch off.
  • Odd Smells: If the air escaping your furnace has a powerful chemical scent, it may be a sign gas is leaking through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm is triggered or you feel health problems: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm could go off or household members could struggle with signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If your alarm goes off or you feel unusually tired, get out of the home immediately and then call for help.
  • Soot: If you find black sooty collecting near the exterior of your furnace, it’s an indication 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 professional with extensive experience in furnace installation Lafayette right away so they can inspect your system and, if needed, perform a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates often hover around $1,000 to $3,000.

Fortunately, the good news is that heat exchangers are generally covered by the warranty. You’ll want to check the warranty paperwork on your furnace, because while the warranty may not cover the entire cost of repairs, it still may 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 through consistent furnace maintenance. Furnaces provide the best possible return on investment when they run efficiently. Hiring a skilled professional to check your furnace for old parts, dirty filters and other potential problems can keep you from getting a big bill later on.

It’s also helpful 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 drawing air through a clogged filter makes the entire furnace work harder to accomplish its job. And the harder your furnace has to work, the more strain components like the heat exchanger will endure.