A furnace is usually a background player in your home, keeping you warm across the cold winter months. It often doesn’t get noticed until a malfunction appears.
One source might be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s worthwhile to learn 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 in your furnace to the air that flows through the system. It usually accomplishes this via coils or tubes that heat the air while serving as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from leaking out into your home.
Is a Cracked Heat Exchanger Dangerous?
Because of its key role, it isn't surprising that a damaged heat exchanger can be very dangerous. A damaged heat exchanger can allow dangerous gasses – such as carbon monoxide, which can be lethal – to circulate across your home.
For obvious reasons, don't ever turn on your heater if you think it has a cracked heat exchanger, as this could make your entire family ill. Contact an HVAC professional right away if you believe your furnace has a cracked heat exchanger that needs repair.
Four Signs of a Cracked Heat Exchanger:
- Furnace shuts off: Cracks in the heat exchanger can cause your furnace to turn off.
- Strange Smells: If the air leaving your furnace has an intense chemical smell, it may be evidence gas is leaking through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm goes off or you notice symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm may go off or family members may experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel sick, get out of the home right away and then call for help.
- Soot: If you find black sooty collecting near the exterior of your furnace, it’s more evidence something may be seriously wrong.
What to Do if the Furnace Heat Exchanger is Cracked
If you believe your furnace has a cracked heat exchanger, call a pro experienced in furnace installation right away so they can inspect your system and, if necessary, handle a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.
Estimates aside, the good news is that heat exchangers are regularly included in the warranty. You’ll want to confirm 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 Prevent a Cracked Heat Exchanger in Your Home
One of the easiest ways to prevent a problem in your furnace overall is with routine furnace maintenance. Furnaces provide the best possible return on investment when they run efficiently. Contacting a trained professional to inspect your furnace for worn-out parts, clogged filters and other likely problems can keep you from getting a big bill later on.
It’s also a good idea to take a look at 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 connected to the heat exchanger itself, the strain of drawing air through a clogged filter makes your entire furnace work harder to complete its job. And the harder your furnace needs to run, the more deterioration parts like the heat exchanger will endure.