A furnace is often a background player at home, helping keep you warm in the cold winter months. It regularly doesn’t get noticed until a malfunction appears.
One cause could be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s important to know the signs of a cracked heat exchanger and what to do if you believe that may be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps move heat from the combustion chamber inside your furnace to the air that circulates through the ventilation. It typically does this through coils or tubes that warm the air while acting as a barrier to keep gas 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’s no surprise that a broken heat exchanger can be very dangerous. A damaged heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to be distributed through your home.
For this reason, do NOT run your heater if you think it has a cracked heat exchanger, as letting it run could make the whole family sick. Reach out to an HVAC professional as soon as possible if you believe your furnace has a cracked heat exchanger that should be repaired.
Four 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 coming out of your furnace has a powerful chemical scent, it might be evidence gas is seeping through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm goes off or you feel poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm may go off or household members could start experiencing signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. 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 notice black sooty accumulating around the exterior of your furnace, it’s an indication something might be seriously wrong.
What to Do if Your Furnace Heat Exchanger is Cracked
If you worry your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation right away so they can take a look at your system and, if required, perform a furnace heat exchanger replacement. Costs often vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.
However, the good news is that heat exchangers are generally covered by the warranty. You should check the warranty paperwork on your furnace, as while the warranty may not cover the entire cost of repairs, it still may significantly shrink your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the most convenient ways to minimize the risk of problems in your furnace overall is through routine furnace maintenance. Furnaces work the best when they operate efficiently. Contacting a trained professional to inspect your furnace for old parts, clogs in the air filters and other likely problems can keep you from getting a big bill later on.
It’s also helpful 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 aren't a part of the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work harder to complete its job. And the harder your furnace needs to run, the more wear and tear pieces like the heat exchanger will experience.