A furnace is usually a background player in your home, ensuring you're warm during the cold winter months. It often isn't noticed until something breaks down.
One source could be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s worthwhile to learn the signs of a cracked heat exchanger and what you can do if you believe that may be 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 circulates throughout the system. It generally does this via coils or tubes that warm the air while serving as a barrier to keep the gasses produced in the combustion chamber, called flue gasses, from getting out into your home.
Is a Cracked Heat Exchanger Dangerous?
Thanks to its important role, it shouldn't come as a surprise that a cracked heat exchanger can pose a risk. A damaged heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to circulate through your home.
For this reason, don't ever run your furnace if you believe it has a cracked heat exchanger, as letting it run could make the entire household ill. Contact an HVAC professional as soon as possible if you are worried your heating 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 switch off.
- Strange Smells: If the air coming out of your furnace has a powerful chemical odor, it might be evidence gasses are leaking through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a common warning sign.
- Carbon monoxide alarm goes off or you recognize health problems: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm may go off or household members might struggle with signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If your alarm goes off or you feel unusually tired, get out of the home immediately and then call for help.
- Soot: If you find black sooty collecting near the exterior of your furnace, it’s an indication something could be seriously wrong.
What You Should Do if Your Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation as soon as possible so they can inspect your system and, if needed, handle a furnace heat exchanger replacement. Costs often 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 regularly protected by the warranty. You should review the warranty paperwork on your furnace, as while the warranty might not cover the entire cost of repairs, it could significantly shrink your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the most convenient ways to avoid problems in your furnace overall is through regular furnace maintenance. Furnaces offer the most benefits when they run efficiently. Contacting a trained professional to inspect your furnace for worn-out parts, dirty filters and other likely problems can keep you from getting a big bill later on.
It’s also helpful 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 dragging air through a clogged filter makes your entire furnace work more vigorously to do its job. And the harder your furnace has to work, the more deterioration pieces like the heat exchanger will endure.