Cracked Heat Exchanger: What That Means and What to Do Next

September 20, 2022

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

One cause could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s critical to learn the symptoms of a cracked heat exchanger and what to do if you are worried that is the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger transfers heat from the combustion chamber inside your furnace to the air that moves inside the air ducts. It usually accomplishes this with coils or tubes that heat the air while functioning as a barrier to keep gas created in the combustion chamber, called flue gasses, from getting out into your home.

Is a Cracked Heat Exchanger Dangerous?

Given its key role, it shouldn't come as a surprise that a broken heat exchanger can pose a risk. A damaged heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home.

For this reason, never run your heater if you believe there's a crack in the heat exchanger, as letting it run could make the whole household sick. Contact an HVAC professional as soon as possible if you believe your heater has a cracked heat exchanger that should be repaired.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace shuts off: Cracks in the heat exchanger may cause your furnace to turn off.
  • Strange Smells: If the air escaping your furnace has a powerful chemical odor, it might be evidence gasses are seeping through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a major warning sign.
  • Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm could go off or household members may struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If your alarm goes off or you feel unusually tired, exit the home as soon as you can and then call for help.
  • Soot: If you see black sooty collecting around the exterior of your furnace, it’s an indication something could 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 pro experienced in furnace installation West Valley City as soon as possible so they can examine your system and, if needed, perform a furnace heat exchanger replacement. Costs often differ depending on the situation, but estimates often hover around $1,000 to $3,000.

Fortunately, the good news is that heat exchangers are often included in the warranty. You’ll want to confirm the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it can significantly reduce your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the easiest ways to prevent a problem in your furnace overall is through regular furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Calling a trained professional to inspect your furnace for worn-out parts, clogs in the air filters and other likely problems can help you avoid 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 a part of the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work harder to do its job. And the harder your furnace works, the more wear and tear parts like the heat exchanger will experience.