A furnace is almost always a background player for your home, ensuring you're warm during the cold winter months. It often won't be noticed until a malfunction appears.
One source could be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s worthwhile to learn the signs of a cracked heat exchanger and what you can do if you believe that may be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps move heat from the combustion chamber inside your furnace to the air that circulates inside the air ducts. It generally does this using coils or tubes that heat the air while acting 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’s no surprise that a cracked heat exchanger can be hazardous. A crack in the heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to be distributed through your home.
For this reason, never use your heating if you believe it has a cracked heat exchanger, as this could make the whole household sick. Reach out to an HVAC professional right away if you are worried your heating has a cracked heat exchanger that needs to be repaired.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace shuts off: Cracks in the heat exchanger can cause your furnace to switch off.
- Unusual Smells: If the air coming out of your furnace has a powerful chemical odor, it might be a sign gas is seeping through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a common warning sign.
- Carbon monoxide alarm goes off or you recognize poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm could go off or family members may struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel unwell, get out of the home right away and then call for help.
- Soot: If you notice black sooty buildup on the exterior of your furnace, it’s another sign something might be seriously wrong.
What You Can Do if a Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, contact a pro with extensive experience in furnace installation right away so they can inspect your system and, if needed, handle a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000.
Fortunately, the good news is that heat exchangers are regularly protected by the warranty. It's a good idea to review the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it still may significantly shrink 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 through consistent furnace maintenance. Furnaces work the best when they work efficiently. Calling a skilled professional to check your furnace for worn-out parts, clogged 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 are not part of the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work longer to accomplish its job. And the harder your furnace works, the more deterioration components like the heat exchanger will endure.