A furnace is almost always a background player for your home, ensuring you're warm across the cold winter months. It frequently isn't noticed until a malfunction appears.
One root cause could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to learn the signs of a cracked heat exchanger and what you should do if you suspect that might be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps transition heat from the combustion chamber in your furnace to the air that circulates inside the air ducts. It typically does this through coils or tubes that warm the air while functioning as a barrier to keep byproducts formed in the combustion chamber, called flue gasses, from getting out into your home.
Is a Cracked Heat Exchanger Dangerous?
Thanks to its central role, it isn't surprising that a broken heat exchanger can be hazardous. Cracks in the heat exchanger can enable dangerous gasses – such as carbon monoxide, which can be lethal – to be distributed across your home.
For obvious reasons, do NOT turn on your heating if you think it has a cracked heat exchanger, as letting it run could make the whole household sick. Reach out to an HVAC professional right away if you are worried your heating has a cracked heat exchanger that should be repaired.
Four Symptoms of a Cracked Heat Exchanger:
- Furnace turns off: A cracked heat exchanger could cause your furnace to shut off.
- Odd Smells: If the air leaving your furnace has an intense chemical smell, it could be an indicator that gasses are seeping through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm goes off or you feel health problems: If a cracked heat exchanger is relieving carbon monoxide into your home, your carbon monoxide alarm may go off or family members could experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an alarm goes off or you feel unwell, exit the home immediately and then call for help.
- Soot: If you spot black sooty accumulating on the exterior of your furnace, it’s more evidence something might be seriously wrong.
What You Can Do if Your Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, contact a pro with extensive experience in furnace installation right away so they can inspect your system and, if required, handle 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 regularly covered by the warranty. You should check the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it could significantly lower your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the easiest ways to avoid problems in your furnace overall is with routine furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Hiring a certified professional to check your furnace for old parts, clogged filters and other potential problems can keep you from getting a big bill later on.
It’s also helpful 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 dragging air through a clogged filter makes the entire furnace work longer to complete its job. And the harder your furnace has to work, the more wear and tear pieces like the heat exchanger will endure.