A furnace is almost always a background player in your home, ensuring you're warm across the cold winter months. It often won't be noticed until something breaks down.
One source might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s critical to know the symptoms of a cracked heat exchanger and what you should do if you suspect that may be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps move heat from the combustion chamber of your furnace to the air that flows through the system. It typically does this with coils or tubes that heat up the air while functioning as a barrier to keep the gasses created in the combustion chamber, called flue gasses, from leaking out into your home.
Is a Cracked Heat Exchanger Dangerous?
Thanks to its important role, it shouldn't come as a surprise that a damaged heat exchanger can be hazardous. Cracks in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to be distributed across your home.
For obvious reasons, don't ever use your heating if you suspect it has a cracked heat exchanger, as doing so could make the whole family sick. Contact an HVAC professional right away if you think your heating has a cracked heat exchanger that needs to be repaired.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace switches off: A crack in your heat exchanger can cause your furnace to turn off.
- Strange Smells: If the air coming out of your furnace has a powerful chemical scent, it may be evidence gas is slipping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a common warning sign.
- Carbon monoxide alarm initiates or you notice poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide inside your home, your carbon monoxide alarm should go off or household members may start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unusually tired, get out of the home immediately and then call for help.
- Soot: If you notice black sooty buildup near the exterior of your furnace, it’s an indication something may be seriously wrong.
What You Should Do if Your Furnace Heat Exchanger is Cracked
If you worry your furnace has a cracked heat exchanger, call a professional experienced in furnace installation as soon as possible so they can inspect your system and, if needed, perform a furnace heat exchanger replacement. Costs should vary 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 covered by the warranty. It's a good idea to confirm the warranty paperwork on your furnace, as while the warranty may not cover the entire cost of repairs, it could significantly lower 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 with consistent furnace maintenance. Furnaces work the best when they work efficiently. Hiring a certified professional to check your furnace for old parts, dirty filters and other likely problems can help you avoid getting a big bill later on.
It’s also beneficial to take a look at your furnace filters every few months – it’s encouraged some filters be swapped out 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 pulling air through a clogged filter makes the entire furnace work more vigorously to complete its job. And the harder your furnace has to work, the more deterioration parts like the heat exchanger will experience.