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

September 20, 2022

A furnace is almost always a background player at home, helping keep you warm during the cold winter months. It frequently won't be noticed until something breaks down.

One cause may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s worthwhile to learn the evidence 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 usually does this via coils or tubes that heat the air while acting as a barrier to keep gas produced in the combustion chamber, called flue gasses, from escaping out into your home.

Is a Cracked Heat Exchanger Dangerous?

Given its key role, it’s no surprise 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 be distributed throughout your home.

For obvious reasons, never turn on your heating if you believe you're dealing with a cracked heat exchanger, as this could make your entire household ill. Contact an HVAC professional immediately if you believe your heating has a cracked heat exchanger that should be repaired.

Four Signs of a Cracked Heat Exchanger:

  • Furnace switches off: Cracks in the heat exchanger can cause your furnace to shut off.
  • Unusual Smells: If the air coming out of your furnace has a powerful chemical odor, it could be evidence gas is leaking through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a common warning sign.
  • Carbon monoxide alarm initiates or you feel symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm may go off or family members could start experiencing 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 right away and then call for help.
  • Soot: If you notice black sooty buildup near the exterior of your furnace, it’s more evidence something may be seriously wrong.

What to Do if a Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, call a professional well versed in furnace installation Racine as soon as possible so they can inspect your system and, if necessary, handle a furnace heat exchanger replacement. Costs often vary depending on the situation, but estimates often hover around $1,000 to $3,000.

However, the good news is that heat exchangers are regularly included in the warranty. It's a good idea to review the warranty paperwork on your furnace, because while the warranty won't always cover the entire cost of repairs, it still may significantly shrink your bill.

How to Prevent a Cracked Heat Exchanger in Your Home

One of the most convenient ways to avoid problems in your furnace overall is via regular furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Hiring a skilled professional to inspect your furnace for worn-out parts, clogs in the air filters and other common problems can help you avoid getting a big bill later on.

It’s also helpful to inspect your furnace filters every few months – it’s encouraged some filters be replaced every 90 days or sooner if they are dirty or grimy. While the filters are not 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 has to work, the more wear and tear parts like the heat exchanger will endure.