A furnace is almost always a background player for your home, keeping you warm in the cold winter months. It regularly doesn’t get noticed until something goes wrong.
One source could be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s worthwhile to know the evidence of a cracked heat exchanger and what you should do if you are worried 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 flows throughout the air ducts. It generally handles this using coils or tubes that heat up 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?
Thanks to its key role, it isn't surprising that a damaged heat exchanger can be hazardous. A crack in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to be distributed through your home.
For obvious reasons, never run your heating if you think you're dealing with a cracked heat exchanger, as this could make the entire family ill. Reach out to an HVAC professional immediately if you think your heating has a cracked heat exchanger that needs repair.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace shuts off: A cracked heat exchanger could cause your furnace to shut off.
- Unusual Smells: If the air leaving your furnace has a strong chemical scent, it could be a sign gasses are slipping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm goes off or you notice symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm should go off or household members could experience 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, get out of the home right away and then call for help.
- Soot: If you spot black sooty accumulating near the exterior of your furnace, it’s an indication something could be seriously wrong.
What to Do if a Furnace Heat Exchanger is Cracked
If you worry your furnace has a cracked heat exchanger, hire a professional experienced in furnace installation right away so they can take a look at your system and, if necessary, perform a furnace heat exchanger replacement. Costs often differ 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 generally included in the warranty. It's a good idea to check the warranty paperwork on your furnace, as while the warranty might not cover the entire cost of repairs, it still may significantly reduce your bill.
How to Prevent a Cracked Heat Exchanger in Your Home
One of the most convenient ways to prevent a problem in your furnace overall is through regular furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Contacting a trained professional to check your furnace for broken-down parts, clogged filters and other potential problems can help you avoid getting a big bill later on.
It’s also helpful to take a look at your furnace filters every few months – it’s recommended some filters be swapped out 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 more vigorously to do its job. And the harder your furnace works, the more deterioration components like the heat exchanger will endure.