A furnace is often a background player in your home, ensuring you're warm across the cold winter months. It frequently won't be noticed until something goes wrong.
One cause could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to familiarize yourself with the symptoms of a cracked heat exchanger and what to 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 in your furnace to the air that flows throughout the ventilation. It typically does this using coils or tubes that heat up the air while serving as a barrier to keep gas created in the combustion chamber, called flue gasses, from leaking out into your home.
Is a Cracked Heat Exchanger Dangerous?
Given its central role, it isn't surprising that a cracked heat exchanger can be very dangerous. A damaged heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home.
For obvious reasons, don't ever run your heater if you believe there's a crack in the heat exchanger, as doing so could make your entire household ill. Reach out to an HVAC professional as soon as possible if you are worried your heater has a cracked heat exchanger that needs repair.
Four Symptoms of a Cracked Heat Exchanger:
- Furnace shuts off: A cracked heat exchanger may cause your furnace to turn off.
- Odd Smells: If the air coming out of your furnace has a powerful chemical scent, it may be evidence gas is seeping through cracks in your heat exchanger. These byproducts, which may 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 in your home, your carbon monoxide alarm should go off or family members could experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel sick, leave the home right away and then call for help.
- Soot: If you spot black sooty accumulating near the exterior of your furnace, it’s an indication something might 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 professional experienced in furnace installation as soon as possible so they can take a look at your system and, if necessary, start a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000.
Fortunately, the good news is that heat exchangers are often protected by the warranty. You’ll want to check the warranty paperwork on your furnace, because while the warranty may not cover the entire cost of repairs, it can significantly reduce your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the most convenient ways to prevent a problem in your furnace overall is with routine furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Calling a certified professional to check your furnace for old parts, clogs in the air filters and other common problems can keep you from getting a big bill later on.
It’s also beneficial to review your furnace filters every few months – it’s encouraged some filters be replaced 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 pulling air through a clogged filter makes your entire furnace work longer to complete its job. And the harder your furnace works, the more strain parts like the heat exchanger will sustain.