A furnace is usually a background player in your home, keeping you warm during the cold winter months. It often isn't noticed until something breaks down.
One root cause might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s critical to know the symptoms of a cracked heat exchanger and what to do if you are worried that may 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 moves through the ventilation. It generally does this using coils or tubes that heat up the air while acting as a barrier to keep the gasses 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 shouldn't come as a surprise that a damaged heat exchanger can be hazardous. A damaged heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to be distributed across your home.
For obvious reasons, never use your furnace if you suspect there's a crack in the heat exchanger, as this could make the whole family sick. Reach out to an HVAC professional immediately if you think your furnace 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 switch off.
- Unusual Smells: If the air leaving your furnace has a powerful chemical odor, it may be a sign gas is slipping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a common warning sign.
- Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm should go off or family members might experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If your alarm goes off or you feel sick, leave the home as soon as you can and then call for help.
- Soot: If you see black sooty buildup near the exterior of your furnace, it’s an indication something may be seriously wrong.
What to Do if the Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, hire a pro with extensive experience in furnace installation as soon as possible so they can inspect your system and, if required, perform a furnace heat exchanger replacement. Costs often differ depending on the situation, but estimates often hover around $1,000 to $3,000.
However, the good news is that heat exchangers are generally included in the warranty. You’ll want to confirm the warranty paperwork on your furnace, as while the warranty won't always 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 easiest ways to prevent a problem in your furnace overall is through regular furnace maintenance. Furnaces work the best when they run efficiently. Hiring a skilled professional to examine your furnace for old parts, clogs in the air filters and other likely problems can help you avoid getting a big bill later on.
It’s also beneficial to review your furnace filters every few months – it’s ideal 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 dragging air through a clogged filter makes your entire furnace work longer to accomplish its job. And the harder your furnace has to work, the more deterioration parts like the heat exchanger will sustain.