A furnace is usually a background player in your home, keeping you warm during the cold winter months. It frequently doesn’t get noticed until something breaks down.
One source 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 may be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps transition heat from the combustion chamber inside your furnace to the air that circulates inside the air ducts. It generally does this using coils or tubes that warm the air while acting as a barrier to keep the gasses formed in the combustion chamber, called flue gasses, from getting out into your home.
Is a Cracked Heat Exchanger Dangerous?
Given its central role, it’s no surprise that a broken heat exchanger can be very dangerous. A crack in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to circulate across your home.
For obvious reasons, do NOT turn on your furnace if you believe it has a cracked heat exchanger, as doing so could make your entire household ill. Call an HVAC professional as soon as possible if you are worried your heater has a cracked heat exchanger that should be repaired.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace switches off: A crack in your heat exchanger could cause your furnace to turn off.
- Strange Smells: If the air coming out of your furnace has a strong chemical scent, it may be evidence gasses are leaking through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm initiates or you notice symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm may go off or household members could experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If the alarm goes off or you feel unusually tired, get out of the home right away and then call for help.
- Soot: If you spot black sooty accumulating near the exterior of your furnace, it’s more evidence something may be seriously wrong.
What to Do if a Furnace Heat Exchanger is Cracked
If you believe your furnace has a cracked heat exchanger, hire a professional experienced in furnace installation right away so they can inspect your system and, if needed, start a furnace heat exchanger replacement. Costs will differ depending on the situation, but estimates often hover around $1,000 to $3,000.
However, the good news is that heat exchangers are regularly covered by the warranty. You’ll want to check the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it could significantly lower your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the best ways to prevent a problem in your furnace overall is with consistent furnace maintenance. Furnaces offer the most benefits when they run efficiently. Contacting a certified professional to check your furnace for old parts, clogged filters and other likely problems can keep you from getting a big bill later on.
It’s also beneficial to take a look at 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 the entire furnace work harder to complete its job. And the harder your furnace has to work, the more strain components like the heat exchanger will endure.