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

September 20, 2022

A furnace is usually a background player for your home, helping keep you warm in the cold winter months. It often won't be noticed until a malfunction appears.

One root cause could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to know the symptoms of a cracked heat exchanger and what you should do if you suspect that might 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 through the ventilation. It typically handles this via coils or tubes that heat up the air while functioning as a barrier to keep the gasses produced in the combustion chamber, called flue gasses, from leaking out into your home.

Is a Cracked Heat Exchanger Dangerous?

Thanks to its central role, it isn't surprising that a damaged heat exchanger can be very dangerous. Cracks in the heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to flow throughout your home.

For that reason, do NOT turn on your heating if you believe you're dealing with a cracked heat exchanger, as doing so could make the whole family ill. Reach out to an HVAC professional immediately if you believe your heating has a cracked heat exchanger that should be repaired.

Four Warning Signs of a Cracked Heat Exchanger:

  • Furnace switches off: Cracks in the heat exchanger could cause your furnace to shut off.
  • Unusual Smells: If the air leaving your furnace has an intense chemical odor, it may be evidence gasses are leaking through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm initiates or you notice 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 start experiencing signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel unwell, get out of the home as soon as you can and then call for help.
  • Soot: If you notice black sooty collecting around the exterior of your furnace, it’s an indication something may be seriously wrong.

What to Do if Your Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation Safford right away so they can examine your system and, if required, perform a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000.

Estimates aside, the good news is that heat exchangers are often protected by the warranty. You should 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 Avoid a Cracked Heat Exchanger in Your Home

One of the most convenient ways to avoid problems in your furnace overall is with regular furnace maintenance. Furnaces work the best when they work efficiently. Calling a certified professional to examine your furnace for old parts, dirty filters and other likely problems can keep you from getting a big bill later on.

It’s also helpful to inspect your furnace filters every few months – it’s encouraged 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 drawing air through a clogged filter makes the entire furnace work more vigorously to accomplish its job. And the harder your furnace has to work, the more wear and tear pieces like the heat exchanger will endure.