A furnace is often a background player for your home, keeping you warm across the cold winter months. It often doesn’t get noticed until something goes wrong.
One source could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to learn the symptoms of a cracked heat exchanger and what you can do if you suspect that is the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps transition heat from the combustion chamber inside your furnace to the air that moves through the air ducts. It usually does this via coils or tubes that heat the air while functioning as a barrier to keep gas formed in the combustion chamber, called flue gasses, from escaping out into your home.
Is a Cracked Heat Exchanger Dangerous?
Because of its central role, it’s no surprise that a cracked heat exchanger can be very dangerous. A damaged heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to circulate throughout your home.
For obvious reasons, don't ever use your furnace if you think there's a crack in the heat exchanger, as this could make the whole family sick. Reach out to an HVAC professional immediately if you believe your furnace has a cracked heat exchanger that should be repaired.
Four Symptoms of a Cracked Heat Exchanger:
- Furnace switches off: A cracked heat exchanger may cause your furnace to turn off.
- Odd Smells: If the air escaping your furnace has a strong chemical odor, it could be a sign gas is seeping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm goes off or you recognize 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 struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unusually tired, get out of the home as soon as you can and then call for help.
- Soot: If you find black sooty buildup near the exterior of your furnace, it’s another sign something may be seriously wrong.
What You Should Do if Your Furnace Heat Exchanger is Cracked
If you worry your furnace has a cracked heat exchanger, hire a professional experienced in furnace installation as soon as possible so they can inspect your system and, if required, handle a furnace heat exchanger replacement. Costs will differ depending on the situation, but estimates often hover around $1,000 to $3,000.
Estimates aside, the good news is that heat exchangers are often protected by the warranty. It's a good idea to confirm the warranty paperwork on your furnace, since while the warranty might not cover the entire cost of repairs, it still may significantly reduce 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 through routine furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Contacting a certified professional to inspect your furnace for broken-down parts, dirty filters and other potential 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 recommended 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 the entire furnace work longer to do its job. And the harder your furnace has to work, the more strain parts like the heat exchanger will sustain.