A furnace is often a background player for your home, helping keep you warm during the cold winter months. It regularly isn't noticed until something breaks down.
One root cause may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to learn the evidence of a cracked heat exchanger and what you should 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 of your furnace to the air that circulates throughout the air ducts. It usually accomplishes this via coils or tubes that heat up the air while functioning as a barrier to keep the gasses produced in the combustion chamber, called flue gasses, from leaking out into your home.
Is a Cracked Heat Exchanger Dangerous?
Because of its important role, it isn't surprising that a cracked heat exchanger can pose a risk. A crack in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to circulate across your home.
For this reason, do NOT use your heating if you suspect there's a crack in the heat exchanger, as this could make your entire household sick. Contact an HVAC professional right away if you think your heater has a cracked heat exchanger that needs repair.
Four Symptoms of a Cracked Heat Exchanger:
- Furnace switches off: A crack in your heat exchanger could cause your furnace to turn off.
- Unusual Smells: If the air escaping your furnace has a strong chemical smell, it could be an indicator that gas is slipping through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm is triggered or you feel poisoning symptoms: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm may go off or household members may struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. 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 spot black sooty accumulating 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 believe your furnace has a cracked heat exchanger, contact a pro experienced in furnace installation as soon as possible so they can examine your system and, if needed, start a furnace heat exchanger replacement. Costs often vary depending on the situation, but estimates often hover around $1,000 to $3,000.
However, the good news is that heat exchangers are regularly included in the warranty. You should check the warranty paperwork on your furnace, since while the warranty might not cover the entire cost of repairs, it still may significantly shrink 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 through routine furnace maintenance. Furnaces offer the most benefits when they work efficiently. Contacting a skilled professional to check your furnace for old parts, dirty filters and other likely problems can help you avoid getting a big bill later on.
It’s also helpful 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 pulling air through a clogged filter makes the entire furnace work more vigorously to do its job. And the harder your furnace works, the more strain components like the heat exchanger will endure.