A furnace is usually a background player for your home, keeping you warm across the cold winter months. It regularly isn't noticed until something breaks down.
One cause may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s worthwhile to know the symptoms of a cracked heat exchanger and what to do if you are worried that might 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 moves throughout the air ducts. It typically handles this via coils or tubes that warm the air while functioning as a barrier to keep byproducts formed in the combustion chamber, called flue gasses, from leaking out into your home.
Is a Cracked Heat Exchanger Dangerous?
Because of its central role, it’s no surprise that a broken heat exchanger can be very dangerous. Cracks in the heat exchanger can enable dangerous gasses – such as carbon monoxide, which can be lethal – to be distributed throughout your home.
For obvious reasons, do NOT use your heating if you believe it has a cracked heat exchanger, as doing so could make the entire family ill. Reach out to an HVAC professional right away if you believe your heater has a cracked heat exchanger that needs to be repaired.
Four Signs of a Cracked Heat Exchanger:
- Furnace turns off: Cracks in the heat exchanger could cause your furnace to switch off.
- Strange Smells: If the air escaping your furnace has a powerful chemical smell, it may be evidence gas is leaking through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm is triggered or you notice health problems: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm could go off or family members may experience 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, exit the home as soon as you can and then call for help.
- Soot: If you notice black sooty accumulating 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 well versed in furnace installation as soon as possible so they can inspect your system and, if necessary, perform a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates often hover around $1,000 to $3,000.
Fortunately, the good news is that heat exchangers are generally protected by the warranty. It's a good idea to confirm the warranty paperwork on your furnace, because while the warranty won't always 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 prevent a problem in your furnace overall is via consistent furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Hiring a skilled professional to examine your furnace for broken-down parts, clogs in the air filters and other potential problems can help you avoid getting a big bill later on.
It’s also helpful to inspect your furnace filters every few months – it’s ideal 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 drawing air through a clogged filter makes your entire furnace work longer to complete its job. And the harder your furnace needs to run, the more wear and tear parts like the heat exchanger will endure.