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

September 20, 2022

A furnace is almost always a background player for your home, keeping you warm during the cold winter months. It frequently isn't noticed until something goes wrong.

One root cause might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to know the signs of a cracked heat exchanger and what you should do if you are worried that may be 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 ventilation. It generally does this with 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 getting out into your home.

Is a Cracked Heat Exchanger Dangerous?

Given its important role, it isn't surprising that a cracked heat exchanger can be hazardous. A damaged heat exchanger can allow dangerous gasses – such as carbon monoxide, which can be lethal – to flow throughout your home.

For obvious reasons, never turn on your furnace if you think there's a crack in the heat exchanger, as letting it run could make your entire household sick. Reach out to an HVAC professional as soon as possible if you are worried your heating has a cracked heat exchanger that should be repaired.

Four Symptoms of a Cracked Heat Exchanger:

  • Furnace turns off: A crack in your heat exchanger can cause your furnace to shut off.
  • Odd Smells: If the air coming out of your furnace has an intense chemical smell, it may be evidence gas is leaking through cracks in your heat exchanger. These byproducts, which will often smell like formaldehyde, are a common warning sign.
  • Carbon monoxide alarm goes off 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 household members may struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel sick, leave the home immediately and then call for help.
  • Soot: If you see black sooty collecting on the exterior of your furnace, it’s more evidence something could be seriously wrong.

What You Should Do if Your Furnace Heat Exchanger is Cracked

If you believe your furnace has a cracked heat exchanger, contact a professional experienced in furnace installation Derby as soon as possible so they can take a look at your system and, if needed, start a furnace heat exchanger replacement. Costs often fluctuate depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.

Fortunately, the good news is that heat exchangers are often covered by the warranty. It's a good idea to check 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 Avoid a Cracked Heat Exchanger in Your Home

One of the best ways to prevent a problem in your furnace overall is through regular furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Calling a skilled professional to check your furnace for old parts, dirty filters and other common 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 connected to the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work harder to complete its job. And the harder your furnace needs to run, the more strain pieces like the heat exchanger will endure.