A furnace is almost always a background player for your home, keeping you warm across the cold winter months. It frequently isn't noticed until a malfunction appears.
One source might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s critical to familiarize yourself with the evidence of a cracked heat exchanger and what you can do if you are worried that is the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps transition heat from the combustion chamber inside your furnace to the air that circulates inside the ventilation. It usually accomplishes this via coils or tubes that heat the air while serving as a barrier to keep the gasses created 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 shouldn't come as a surprise that a broken heat exchanger can be very dangerous. A crack in the heat exchanger can enable dangerous gasses – such as carbon monoxide, which can be lethal – to flow throughout your home.
For this reason, do NOT turn on your heating if you believe there's a crack in the heat exchanger, as letting it run could make your entire household sick. Contact an HVAC professional immediately if you think your heating has a cracked heat exchanger that should be repaired.
Four Symptoms of a Cracked Heat Exchanger:
- Furnace turns off: Cracks in the heat exchanger could cause your furnace to switch off.
- Odd Smells: If the air leaving your furnace has an intense chemical smell, it may be an indicator that gasses are seeping through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a common warning sign.
- Carbon monoxide alarm goes off or you notice health problems: If a cracked heat exchanger is releasing carbon monoxide inside your home, your carbon monoxide alarm should go off or household members may experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an 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 around the exterior of your furnace, it’s more evidence something could be seriously wrong.
What You Can Do if a Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, contact a professional well versed in furnace installation as soon as possible so they can inspect your system and, if needed, handle a furnace heat exchanger replacement. Costs should vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.
Fortunately, the good news is that heat exchangers are generally included in the warranty. You should check the warranty paperwork on your furnace, because while the warranty may 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 prevent a problem in your furnace overall is via regular furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Contacting a trained professional to examine your furnace for broken-down parts, dirty filters and other likely problems can keep you from getting a big bill later on.
It’s also beneficial to take a look at your furnace filters every few months – it’s recommended 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 the entire furnace work more vigorously to do its job. And the harder your furnace has to work, the more deterioration pieces like the heat exchanger will sustain.