A furnace is almost always a background player for your home, helping keep you warm during 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’s a potentially dangerous issue, so it’s important to know the evidence of a cracked heat exchanger and what you can do if you believe that might 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 flows throughout the ventilation. It usually handles this using coils or tubes that heat the air while acting as a barrier to keep gas formed in the combustion chamber, called flue gasses, from getting out into your home.
Is a Cracked Heat Exchanger Dangerous?
Thanks to its key role, it’s no surprise that a cracked heat exchanger can pose a risk. Cracks in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to flow across your home.
For that reason, never use your heating if you believe it has a cracked heat exchanger, as letting it run could make the whole family ill. Contact an HVAC professional immediately if you believe your heater 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 could cause your furnace to turn off.
- Unusual Smells: If the air escaping your furnace has a powerful chemical smell, it may be a sign gasses are seeping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a major 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 could go off or household members might start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an alarm goes off or you feel sick, get out of the home immediately and then call for help.
- Soot: If you notice black sooty collecting around the exterior of your furnace, it’s an indication something could be seriously wrong.
What to Do if a Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, call a pro experienced in furnace installation right away so they can take a look at your system and, if necessary, handle a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000.
Fortunately, the good news is that heat exchangers are regularly included in the warranty. You’ll want to review the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it could significantly shrink your bill.
How to Prevent a Cracked Heat Exchanger in Your Home
One of the best ways to prevent a problem in your furnace overall is via routine furnace maintenance. Furnaces work the best when they run efficiently. Contacting a trained professional to check your furnace for broken-down parts, clogged filters and other potential problems can keep you from getting a big bill later on.
It’s also helpful to take a look at your furnace filters every few months – it’s encouraged some filters be changed 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 pulling air through a clogged filter makes your entire furnace work harder to do its job. And the harder your furnace works, the more deterioration components like the heat exchanger will endure.