A furnace is usually a background player at home, helping keep you warm across the cold winter months. It regularly doesn’t get noticed until a malfunction appears.
One cause may be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s important to learn the signs of a cracked heat exchanger and what to do if you are worried that might be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger transfers heat from the combustion chamber in your furnace to the air that circulates throughout the ventilation. It typically accomplishes this with coils or tubes that heat up the air while functioning as a barrier to keep gas formed in the combustion chamber, called flue gasses, from getting 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. A damaged heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to circulate across your home.
For obvious reasons, do NOT use your heating if you think you're dealing with a cracked heat exchanger, as doing so could make your entire family ill. Contact an HVAC professional as soon as possible if you are worried your heating has a cracked heat exchanger that should be repaired.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace switches off: A cracked heat exchanger could cause your furnace to switch off.
- Unusual Smells: If the air escaping your furnace has a powerful chemical odor, it may be an indicator that gas is seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is emitting carbon monoxide inside your home, your carbon monoxide alarm should go off or family members could struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an alarm goes off or you feel unusually tired, exit the home right away and then call for help.
- Soot: If you see black sooty accumulating on the exterior of your furnace, it’s an indication something could be seriously wrong.
What You Should Do if the Furnace Heat Exchanger is Cracked
If you worry your furnace has a cracked heat exchanger, call a pro well versed in furnace installation right away so they can examine your system and, if required, start a furnace heat exchanger replacement. Costs often vary depending on the situation, but estimates often hover around $1,000 to $3,000.
Estimates aside, the good news is that heat exchangers are regularly protected by the warranty. It's a good idea to 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 Prevent a Cracked Heat Exchanger in Your Home
One of the best ways to prevent a problem in your furnace overall is via routine furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Hiring a skilled professional to inspect your furnace for old parts, clogs in the air filters and other common problems can keep you from getting a big bill later on.
It’s also beneficial to take a look at your furnace filters every few months – it’s ideal some filters be changed 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 dragging air through a clogged filter makes the entire furnace work longer to accomplish its job. And the harder your furnace needs to run, the more wear and tear components like the heat exchanger will sustain.