A furnace is often a background player at home, helping keep you warm across the cold winter months. It often doesn’t get noticed until something breaks down.
One cause may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to know the symptoms of a cracked heat exchanger and what to do if you are worried that may be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps move heat from the combustion chamber of your furnace to the air that moves inside the system. It typically accomplishes this with coils or tubes that warm the air while functioning 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 important role, it isn't surprising that a cracked heat exchanger can be very dangerous. A crack in the heat exchanger can permit dangerous gasses – including carbon monoxide, which can be lethal – to flow throughout your home.
For that reason, do NOT use your heating if you suspect it has a cracked heat exchanger, as this could make the whole household ill. Contact an HVAC professional right away if you think your furnace has a cracked heat exchanger that needs repair.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace turns off: A cracked heat exchanger can cause your furnace to shut off.
- Odd Smells: If the air escaping your furnace has a strong chemical odor, it could be an indicator that gasses are leaking through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm goes off or you notice health problems: If a cracked heat exchanger is relieving carbon monoxide inside your home, your carbon monoxide alarm could go off or household members might experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If the alarm goes off or you feel unusually tired, leave the home as soon as you can and then call for help.
- Soot: If you notice black sooty buildup on the exterior of your furnace, it’s another sign something could be seriously wrong.
What You Can Do if Your Furnace Heat Exchanger is Cracked
If you believe your furnace has a cracked heat exchanger, hire a professional with extensive experience in furnace installation as soon as possible so they can inspect your system and, if required, handle a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000.
Estimates aside, the good news is that heat exchangers are often included in the warranty. You’ll want to confirm the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it can significantly reduce your bill.
How to Prevent a Cracked Heat Exchanger in Your Home
One of the best ways to prevent a problem in your furnace overall is with routine furnace maintenance. Furnaces offer the most benefits when they work efficiently. Calling a skilled professional to examine your furnace for broken-down parts, clogs in the air filters and other potential problems can help you avoid getting a big bill later on.
It’s also a good idea to inspect your furnace filters every few months – it’s recommended 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 more vigorously to complete its job. And the harder your furnace has to work, the more wear and tear pieces like the heat exchanger will endure.