A furnace is often a background player for your home, keeping you warm during the cold winter months. It regularly won't be noticed until something goes wrong.
One cause may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to know the signs 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 helps move heat from the combustion chamber in your furnace to the air that moves throughout the air ducts. It typically handles this using coils or tubes that heat up the air while serving as a barrier to keep byproducts produced in the combustion chamber, called flue gasses, from leaking out into your home.
Is a Cracked Heat Exchanger Dangerous?
Thanks to its central role, it shouldn't come as a surprise that a cracked heat exchanger can be very dangerous. A crack in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to circulate through your home.
For that reason, never use your heating if you believe you're dealing with a cracked heat exchanger, as this could make your entire family sick. Reach out to 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: Cracks in the heat exchanger may cause your furnace to turn off.
- Odd Smells: If the air escaping your furnace has a strong chemical smell, it may be a sign gas is slipping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm initiates or you notice health problems: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm could go off or household members may experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel unusually tired, exit the home right away and then call for help.
- Soot: If you see black sooty accumulating around the exterior of your furnace, it’s more evidence something could be seriously wrong.
What You Should Do if the Furnace Heat Exchanger is Cracked
If you believe your furnace has a cracked heat exchanger, call a professional well versed in furnace installation right away so they can inspect your system and, if required, start a furnace heat exchanger replacement. Costs often vary depending on the situation, but estimates often hover around $1,000 to $3,000.
However, the good news is that heat exchangers are regularly protected by the warranty. It's a good idea to review 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 easiest ways to avoid problems in your furnace overall is via consistent furnace maintenance. Furnaces work the best when they operate efficiently. Contacting a trained professional to check your furnace for worn-out parts, dirty filters and other common problems can keep you from getting a big bill later on.
It’s also a good idea to inspect 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 aren't connected to the heat exchanger itself, the strain of drawing air through a clogged filter makes your entire furnace work more vigorously to accomplish its job. And the harder your furnace has to work, the more strain components like the heat exchanger will experience.
