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

September 20, 2022

A furnace is usually a background player at home, ensuring you're warm during the cold winter months. It regularly isn't 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 critical to know the signs of a cracked heat exchanger and what you should do if you suspect that is 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 moves inside the air ducts. It generally does this via coils or tubes that heat up the air while serving as a barrier to keep gas 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 shouldn't come as a surprise that a damaged heat exchanger can be very dangerous. Cracks in the heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to flow throughout your home.

For this reason, do NOT turn on your heater if you think it has a cracked heat exchanger, as doing so could make the whole household sick. Call an HVAC professional immediately if you think your heater has a cracked heat exchanger that needs to be repaired.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace turns off: A crack in your heat exchanger could cause your furnace to turn off.
  • Odd Smells: If the air leaving your furnace has a strong chemical odor, it might be evidence gas is seeping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm goes off or you recognize health problems: If a cracked heat exchanger is releasing carbon monoxide inside your home, your carbon monoxide alarm could go off or household members might struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel unwell, exit the home right away and then call for help.
  • Soot: If you find black sooty buildup on the exterior of your furnace, it’s another sign 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, contact a professional experienced in furnace installation Wausau as soon as possible so they can examine your system and, if necessary, start a furnace heat exchanger replacement. Costs will differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000.

Estimates aside, the good news is that heat exchangers are generally protected by the warranty. You should check the warranty paperwork on your furnace, since while the warranty may not cover the entire cost of repairs, it still may significantly reduce your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the easiest ways to minimize the risk of problems in your furnace overall is with routine furnace maintenance. Furnaces work the best when they work efficiently. Calling a skilled professional to check your furnace for old parts, clogged filters and other likely problems can keep you from getting a big bill later on.

It’s also a good idea 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 your entire furnace work more vigorously to accomplish its job. And the harder your furnace needs to run, the more deterioration pieces like the heat exchanger will experience.