A furnace is often a background player for your home, helping keep you warm in the cold winter months. It frequently won't be noticed until something breaks down.
One cause might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s important to know the evidence of a cracked heat exchanger and what you should do if you suspect that might be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger transfers heat from the combustion chamber inside your furnace to the air that flows inside the air ducts. It typically accomplishes this with coils or tubes that warm the air while serving 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?
Thanks to its key role, it isn't surprising that a damaged heat exchanger can be very dangerous. Cracks in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to be distributed through your home.
For this reason, never turn on your heating if you suspect there's a crack in the heat exchanger, as this could make the whole family ill. Reach out to an HVAC professional as soon as possible if you are worried 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 can cause your furnace to turn off.
- Strange Smells: If the air coming out of your furnace has a strong chemical smell, it may be an indicator that gasses are slipping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm initiates or you notice symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm should go off or household members might struggle with signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unusually tired, get out of the home immediately and then call for help.
- Soot: If you see black sooty buildup on the exterior of your furnace, it’s another sign something may 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 pro with extensive experience in furnace installation right away so they can take a look at your system and, if needed, start a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000.
Estimates aside, the good news is that heat exchangers are often included in the warranty. It's a good idea to check the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it can significantly shrink your bill.
How to Prevent a Cracked Heat Exchanger in Your Home
One of the easiest ways to prevent a problem in your furnace overall is through regular furnace maintenance. Furnaces provide the best possible return on investment when they run efficiently. Contacting a skilled professional to examine 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 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 aren't a part of the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work longer to accomplish its job. And the harder your furnace needs to run, the more wear and tear components like the heat exchanger will experience.