A furnace is often a background player at home, helping keep you warm across the cold winter months. It frequently won't be noticed until a malfunction appears.
One source may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to know the evidence of a cracked heat exchanger and what you can do if you believe that is the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger transfers heat from the combustion chamber of your furnace to the air that flows inside the air ducts. It usually accomplishes this through coils or tubes that heat up the air while acting as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from escaping out into your home.
Is a Cracked Heat Exchanger Dangerous?
Because of its important role, it’s no surprise that a broken heat exchanger can pose a risk. Cracks in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to be distributed across your home.
For this reason, never run your heating if you suspect you're dealing with a cracked heat exchanger, as letting it run could make the whole household sick. Reach out to an HVAC professional immediately if you believe your furnace has a cracked heat exchanger that needs to be repaired.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace shuts off: A cracked heat exchanger could cause your furnace to shut off.
- Odd Smells: If the air escaping your furnace has an intense chemical smell, it may be an indicator that gas is slipping through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm is triggered or you recognize symptoms of poisoning: If a cracked heat exchanger is relieving carbon monoxide into your home, your carbon monoxide alarm should go off or household members might start experiencing signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unwell, get out of the home immediately and then call for help.
- Soot: If you spot black sooty buildup on the exterior of your furnace, it’s another sign something might be seriously wrong.
What to Do if the Furnace Heat Exchanger is Cracked
If you believe 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 needed, perform a furnace heat exchanger replacement. Costs often vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.
However, the good news is that heat exchangers are regularly included in the warranty. It's a good idea to review the warranty paperwork on your furnace, since 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 minimize the risk of problems in your furnace overall is with regular furnace maintenance. Furnaces work the best when they operate efficiently. Hiring a certified professional to examine your furnace for worn-out parts, clogs in the air filters and other likely problems can keep you from getting a big bill later on.
It’s also a good idea to review your furnace filters every few months – it’s ideal some filters be swapped out 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 accomplish its job. And the harder your furnace works, the more deterioration components like the heat exchanger will sustain.