A furnace is almost always a background player for your home, keeping you warm across the cold winter months. It regularly doesn’t get noticed until something goes wrong.
One cause might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to know the symptoms of a cracked heat exchanger and what to do if you believe that is the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps move heat from the combustion chamber in your furnace to the air that circulates inside the ventilation. It typically accomplishes 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 getting out into your home.
Is a Cracked Heat Exchanger Dangerous?
Given its important role, it’s no surprise that a broken heat exchanger can be hazardous. A damaged heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home.
For this reason, don't ever turn on your furnace if you believe you're dealing with a cracked heat exchanger, as this could make your entire household ill. Call an HVAC professional as soon as possible if you believe your heating has a cracked heat exchanger that should be repaired.
Four Symptoms of a Cracked Heat Exchanger:
- Furnace switches off: A cracked heat exchanger could cause your furnace to switch off.
- Unusual Smells: If the air leaving your furnace has a strong chemical scent, it may be an indicator that gas is seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm is triggered or you feel symptoms of poisoning: If a cracked heat exchanger is relieving carbon monoxide into your home, your carbon monoxide alarm could 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 your alarm goes off or you feel unwell, exit the home right away and then call for help.
- Soot: If you find black sooty buildup on the exterior of your furnace, it’s another sign something might be seriously wrong.
What You Should Do if the Furnace Heat Exchanger is Cracked
If you worry your furnace has a cracked heat exchanger, contact a pro experienced in furnace installation right away so they can inspect your system and, if needed, start a furnace heat exchanger replacement. Costs often differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000.
Fortunately, the good news is that heat exchangers are generally protected by the warranty. You should check the warranty paperwork on your furnace, since while the warranty may not cover the entire cost of repairs, it can significantly reduce your bill.
How to Prevent a Cracked Heat Exchanger in Your Home
One of the most convenient ways to avoid problems in your furnace overall is through regular furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Hiring a skilled professional to examine your furnace for old parts, dirty filters and other likely problems can keep you from getting a big bill later on.
It’s also a good idea to review your furnace filters every few months – it’s ideal some filters be swapped out every 90 days or sooner if they are dirty or grimy. While the filters aren't a part of 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 deterioration parts like the heat exchanger will endure.