A furnace is almost always a background player for your home, helping keep you warm in the cold winter months. It regularly won't be noticed until a malfunction appears.
One source may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s critical to learn the evidence of a cracked heat exchanger and what you should do if you believe that might be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger transfers heat from the combustion chamber in your furnace to the air that circulates through the ventilation. It usually accomplishes this using coils or tubes that heat the air while acting as a barrier to keep byproducts formed in the combustion chamber, called flue gasses, from escaping out into your home.
Is a Cracked Heat Exchanger Dangerous?
Because of its key role, it’s no surprise that a cracked heat exchanger can pose a risk. A crack in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to circulate throughout your home.
For this reason, don't ever run your heater if you suspect it has a cracked heat exchanger, as doing so could make the whole household sick. Reach out to an HVAC professional right away if you think your furnace has a cracked heat exchanger that needs to be repaired.
Four Signs of a Cracked Heat Exchanger:
- Furnace turns off: A cracked heat exchanger can cause your furnace to switch off.
- Strange Smells: If the air coming out of your furnace has a powerful chemical smell, it could be evidence gasses are leaking 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 feel poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide into your home, your carbon monoxide alarm could go off or household members might experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel sick, get out of the home right away and then call for help.
- Soot: If you see black sooty buildup on the exterior of your furnace, it’s more evidence something might be seriously wrong.
What to Do if the Furnace Heat Exchanger is Cracked
If you worry your furnace has a cracked heat exchanger, contact a professional experienced in furnace installation right away so they can take a look at your system and, if necessary, perform a furnace heat exchanger replacement. Costs often differ 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 should check the warranty paperwork on your furnace, since while the warranty may not cover the entire cost of repairs, it could significantly shrink your bill.
How to Prevent a Cracked Heat Exchanger in Your Home
One of the best ways to avoid problems in your furnace overall is through routine furnace maintenance. Furnaces work the best when they operate efficiently. Calling a trained professional to inspect your furnace for worn-out parts, clogs in the air filters and other common problems can keep you from getting a big bill later on.
It’s also a good idea to inspect your furnace filters every few months – it’s ideal some filters be changed every 90 days or sooner if they are dirty or grimy. While the filters aren't a part of the heat exchanger itself, the strain of drawing air through a clogged filter makes your entire furnace work longer to complete its job. And the harder your furnace has to work, the more wear and tear parts like the heat exchanger will sustain.