A furnace is almost always a background player in your home, ensuring you're warm in the cold winter months. It regularly isn't noticed until something goes wrong.
One cause could 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 can do if you are worried 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 moves inside the system. It typically accomplishes this via coils or tubes that heat up the air while functioning as a barrier to keep gas produced in the combustion chamber, called flue gasses, from leaking out into your home.
Is a Cracked Heat Exchanger Dangerous?
Given its important role, it shouldn't come as a surprise that a damaged heat exchanger can be very dangerous. Cracks in the heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to flow through your home.
For that reason, don't ever run your heating if you think it has a cracked heat exchanger, as doing so could make your entire family sick. Reach out to an HVAC professional right away if you are worried your heating has a cracked heat exchanger that should be repaired.
Four Signs of a Cracked Heat Exchanger:
- Furnace turns off: A crack in your heat exchanger may cause your furnace to turn off.
- Strange Smells: If the air coming out of your furnace has a powerful chemical odor, it might be evidence 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 initiates or you notice poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm could go off or household members might start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If the alarm goes off or you feel sick, exit the home as soon as you can and then call for help.
- Soot: If you see black sooty accumulating near the exterior of your furnace, it’s an indication something might be seriously wrong.
What You Should Do if the Furnace Heat Exchanger is Cracked
If you believe your furnace has a cracked heat exchanger, contact a pro experienced in furnace installation right away so they can examine your system and, if required, start a furnace heat exchanger replacement. Costs will 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 included in the warranty. It's a good idea to confirm the warranty paperwork on your furnace, as while the warranty might not cover the entire cost of repairs, it still may significantly lower your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the most convenient ways to minimize the risk of problems in your furnace overall is via routine furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Contacting a certified professional to inspect your furnace for broken-down parts, dirty filters and other potential problems can help you avoid getting a big bill later on.
It’s also helpful to review 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 are not part of the heat exchanger itself, the strain of pulling air through a clogged filter makes your entire furnace work more vigorously to do its job. And the harder your furnace needs to run, the more strain parts like the heat exchanger will sustain.