A furnace is often a background player for your home, helping keep you warm across the cold winter months. It regularly won't be noticed until a malfunction appears.
One root cause may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to know the signs of a cracked heat exchanger and what you should do if you suspect that is the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps move heat from the combustion chamber of your furnace to the air that flows through the system. It generally does this through coils or tubes that heat the air while acting as a barrier to keep byproducts formed in the combustion chamber, called flue gasses, from escaping out into your home.
Is a Cracked Heat Exchanger Dangerous?
Thanks to its key role, it isn't surprising that a damaged heat exchanger can be very dangerous. A damaged heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to flow through your home.
For this reason, don't ever use your heating if you believe there's a crack in the heat exchanger, as doing so could make your entire household sick. Call an HVAC professional right away if you believe your heating has a cracked heat exchanger that needs to be repaired.
Four Symptoms of a Cracked Heat Exchanger:
- Furnace shuts off: Cracks in the heat exchanger could cause your furnace to turn off.
- Strange Smells: If the air leaving your furnace has a strong chemical smell, it could be an indicator that gasses are leaking through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a common warning sign.
- Carbon monoxide alarm is triggered or you recognize poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide inside your home, your carbon monoxide alarm could go off or family members could struggle with signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If the alarm goes off or you feel unusually tired, exit the home immediately and then call for help.
- Soot: If you see black sooty buildup around the exterior of your furnace, it’s an indication something may be seriously wrong.
What You Should Do if a Furnace Heat Exchanger is Cracked
If you believe your furnace has a cracked heat exchanger, hire a pro well versed in furnace installation right away so they can inspect your system and, if needed, start a furnace heat exchanger replacement. Costs will vary 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 generally included in the warranty. You should confirm the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it still may significantly lower your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the best ways to avoid problems in your furnace overall is via consistent furnace maintenance. Furnaces work the best when they run efficiently. Hiring a skilled professional to examine your furnace for broken-down parts, clogged filters and other potential problems can help you avoid getting a big bill later on.
It’s also beneficial 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 a part of the heat exchanger itself, the strain of pulling air through a clogged filter makes your entire furnace work more vigorously to complete its job. And the harder your furnace has to work, the more strain pieces like the heat exchanger will endure.