A furnace is usually a background player in your home, helping keep you warm across the cold winter months. It frequently isn't noticed until something breaks down.
One root cause could be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s worthwhile to familiarize yourself with the evidence 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 transition heat from the combustion chamber in your furnace to the air that flows throughout the air ducts. It typically accomplishes this using 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’s no surprise that a damaged heat exchanger can be very dangerous. A damaged heat exchanger can allow dangerous gasses – such as carbon monoxide, which can be lethal – to circulate throughout your home.
For that reason, never use your heating if you think there's a crack in the heat exchanger, as letting it run could make the whole family ill. Call an HVAC professional right away if you think your heater 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 can cause your furnace to shut off.
- Unusual Smells: If the air escaping your furnace has an intense chemical scent, it might be evidence gasses are leaking through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm initiates or you recognize health problems: If a cracked heat exchanger is releasing carbon monoxide inside your home, your carbon monoxide alarm may go off or family members may struggle with signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel unwell, exit the home as soon as you can and then call for help.
- Soot: If you see black sooty accumulating around the exterior of your furnace, it’s another sign something may be seriously wrong.
What You Can Do if the Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, contact a professional well versed in furnace installation right away so they can inspect your system and, if necessary, perform a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000.
However, the good news is that heat exchangers are often protected by the warranty. It's a good idea to review the warranty paperwork on your furnace, as while the warranty might not cover the entire cost of repairs, it could significantly reduce your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the most convenient ways to avoid problems in your furnace overall is with regular furnace maintenance. Furnaces work the best when they run efficiently. Contacting a skilled professional to inspect your furnace for broken-down parts, dirty filters and other potential problems can help you avoid getting a big bill later on.
It’s also helpful to review your furnace filters every few months – it’s recommended some filters be replaced every 90 days or sooner if they are dirty or grimy. While the filters are not part of the heat exchanger itself, the strain of dragging air through a clogged filter makes the entire furnace work more vigorously to complete its job. And the harder your furnace needs to run, the more deterioration components like the heat exchanger will experience.