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

September 20, 2022

A furnace is usually a background player at home, keeping you warm across the cold winter months. It often isn't noticed until something breaks down.

One source may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s important to familiarize yourself with the symptoms of a cracked heat exchanger and what you should 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 flows inside the system. It usually does this through coils or tubes that warm the air while functioning 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?

Thanks to its important role, it isn't surprising that a cracked heat exchanger can pose a risk. A damaged heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to circulate across your home.

For this reason, don't ever turn on your furnace if you suspect there's a crack in the heat exchanger, as this could make the entire household sick. Reach out to an HVAC professional right away if you believe your heater has a cracked heat exchanger that needs to be repaired.

Four Signs of a Cracked Heat Exchanger:

  • Furnace switches off: A crack in your heat exchanger could cause your furnace to switch off.
  • Unusual Smells: If the air escaping your furnace has a strong chemical scent, it may be evidence gasses are seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a major warning sign.
  • Carbon monoxide alarm goes off or you feel symptoms of poisoning: If a cracked heat exchanger is relieving carbon monoxide into your home, your carbon monoxide alarm may go off or household members may start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel sick, exit the home immediately and then call for help.
  • Soot: If you find black sooty buildup around the exterior of your furnace, it’s more evidence something might 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 with extensive experience in furnace installation Lake Forest as soon as possible so they can take a look at your system and, if required, perform a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000.

However, the good news is that heat exchangers are regularly protected by the warranty. You’ll want to confirm the warranty paperwork on your furnace, since while the warranty might 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 most convenient ways to minimize the risk of problems in your furnace overall is via consistent furnace maintenance. Furnaces work the best when they operate efficiently. Contacting a skilled professional to inspect your furnace for broken-down parts, clogs in the air filters and other likely problems can keep you from getting a big bill later on.

It’s also a good idea to take a look at your furnace filters every few months – it’s recommended some filters be changed 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 dragging air through a clogged filter makes the entire furnace work harder to accomplish its job. And the harder your furnace needs to run, the more strain parts like the heat exchanger will sustain.