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

September 20, 2022

A furnace is often a background player for your home, ensuring you're warm across the cold winter months. It often isn't noticed until something goes wrong.

One source could be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s important to learn the symptoms of a cracked heat exchanger and what to do if you are worried that might be the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger helps move heat from the combustion chamber of your furnace to the air that moves through the air ducts. It typically handles this through coils or tubes that heat up the air while serving as a barrier to keep the gasses created in the combustion chamber, called flue gasses, from leaking out into your home.

Is a Cracked Heat Exchanger Dangerous?

Because of its important role, it shouldn't come as a surprise that a cracked heat exchanger can be very dangerous. Cracks in the heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to be distributed across your home.

For this reason, never run your heating if you believe you're dealing with a cracked heat exchanger, as doing so could make the entire family sick. Contact an HVAC professional immediately if you think your furnace has a cracked heat exchanger that needs repair.

Four Signs of a Cracked Heat Exchanger:

  • Furnace shuts off: A crack in your heat exchanger could cause your furnace to switch off.
  • Odd Smells: If the air escaping your furnace has a powerful chemical smell, it might be an indicator that gasses are seeping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm is triggered or you recognize symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm may go off or family members may struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unusually tired, exit the home immediately and then call for help.
  • Soot: If you spot black sooty collecting around the exterior of your furnace, it’s another sign something could be seriously wrong.

What You Can Do if the Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation Pacheco as soon as possible so they can take a look at your system and, if necessary, handle 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 regularly included in 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 still may significantly lower your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the best ways to avoid problems in your furnace overall is with routine furnace maintenance. Furnaces offer the most benefits when they work efficiently. Contacting a skilled professional to check your furnace for worn-out parts, dirty filters and other likely problems can help you avoid getting a big bill later on.

It’s also beneficial to take a look at 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 pulling air through a clogged filter makes your entire furnace work longer to complete its job. And the harder your furnace needs to run, the more strain pieces like the heat exchanger will sustain.