You may have never heard the term heat exchanger, or if you have, it’s in regard to a problem with your furnace and heating.
You’re in luck, because this article will help you to quickly understand what a heat exchanger is, how it works, why it matters to your heating, and best practices for maintaining your heat exchanger and avoiding scams involving heat exchangers.
That’s a lot to cover in a short amount of time, so let’s get moving.
What Is a Furnace Heat Exchanger?
A heat exchanger is one of the major parts of a home’s furnace. It protects other heating equipment, keeps the air in your home safe to breathe, and helps the furnace to maintain temperature equilibrium to properly heat your home.
That’s a lot for one component, and it’s why the heat exchanger is one of the more important (and most expensive) parts in your system!
Secondary heat exchangers exist in a lot of systems, and the exchanger interacts with the blower motor, ductwork, exhaust pipe, condensate drain and more within your system.
If a heat exchanger isn’t working properly, it can cause a full system shutdown, melt other components in your system, and raise carbon monoxide levels in your home to dangerous levels.
How Do Heat Exchangers Work?
Your gas furnace system produces byproducts which can be harmful. When your system runs, it can produce carbon monoxide (CO), carbon dioxide, nitrous oxide and other chemicals. While not all of these are harmful at low levels, improper heating operation can make them dangerous.
Heat exchangers separate combustion byproducts from the air so that the warm air that’s sent into your home is safe to breathe.
The byproducts are vented through a flue pipe. The size and trajectory of this exhaust will differ depending on the efficiency of the furnace you have, but this separation is necessary for safe operation.
Furnace systems can have up to two heat exchangers. The presence of a second heat exchanger means that your system will be more efficient. Less heat will be loss, and more will be transferred into your home.
A heat exchanger also isn’t a single component, but rather a series of tubes, sheets, fins, wheels and other smaller parts. These work together to transfer safe, warm air to your home.
Cracked Heat Exchangers
If you’ve ever had to discuss heat exchangers, it’s probably in regard to a cracked one.
This is a huge problem with any furnace and needs to be addressed quickly.
However, the urgent need to fix a cracked exchanger is also used by some shady companies to scam homeowners into getting HVAC work done that they don’t need.
Below, we discuss what happens when a heat exchanger cracks, common symptoms, and how to avoid being scammed when your heat exchanger isn’t actually cracked.
Signs of a Cracked Heat Exchanger
One of the largest and most alarming signs of a cracked heat exchanger is what’s known as flame roll out.
This refers to flames literally rolling out of the exchanger and into other areas of your furnace’s internal workings.
This is part of the reason repairs can be extremely costly. These flames can easily damage other parts of your furnace or make it inoperable by melting internal components such as electrical wiring.
Another frequent sign is carbon monoxide (CO) levels. You may not have specific equipment to monitor CO levels in different parts of your HVAC system, but you should have working CO detectors in your home. If these alarms go off, your heat exchanger is one possible cause of it.
Lastly, all the little things that can go wrong with a furnace can be a sign of a cracked heat exchanger. Do you notice odd smells around the system? Is it short cycling while trying to heat your home? Does the air from your vents seem to be less warm than usual?
There are numerous reasons these things could be happening, but your heat exchanger is one of them.
Heat Exchanger Scams vs. Reality
One of the most unfortunate things that happens here is that HVAC companies will scam homeowners into thinking that they have a cracked heat exchanger when they don’t. The cost for either a repair or replacement will be thousands of dollars!
The reason for this is that technicians will often get a hefty commission for convincing a homeowner that they need a new system. Claims of a cracked heat exchanger are one of the easiest ways to do that.
Even worse, if you really do have a cracked heat exchanger, it’s a legitimate danger to your home and a drain on your energy costs and home comfort. So it’s not the type of problem you can afford to ignore.
The types of scams vary. Some will simply rely on the customer’s lack of understanding to claim a crack. Others will use different metrics to try to convince a customer. We’ve even heard of some unscrupulous companies drawing a “crack” on the heat exchanger and trusting that the customer won’t be able to tell the difference.
So how do you prevent being the victim of a scam? A few ways:
- A problematic crack will almost always be visible to the naked eye. If it’s not obvious to you, it may not be an issue.
- CO levels will be elevated. A reading of 50ppm or higher in your exhaust flue is a clear sign that something’s amiss. Any licensed technician will be able to show you these levels.
- If you’re still in doubt, you can always get a second opinion. There might be a small diagnostic fee for the visit, but this beats spending thousands on a repair or replacement you don’t actually need.
Repairing Heat Exchanger vs. Replacing Furnace
Let’s say there really is a problem with your heat exchanger, though. What then?
This is where it becomes a personal decision, but your HVAC contractor can provide information to help you make the best decision for your home.
This includes the fact that heat exchangers, unfortunately, are costly. They’re among the most expensive single parts in a furnace, and installation of a new one might require other adjacent parts be replaced as well.
Another factor is the current age of your furnace. If it’s an older furnace, you’d benefit from an upgrade anyway, and might end up paying for a costly repair now only to pay for an even more expensive full system replacement in just a few years.
No one likes an unexpected HVAC bill. There’s often no great news when it comes to repairing or replacing a heat exchanger. However, the greater short-term cost of replacing your furnace can sometimes be less costly in the long run, particularly if you expect to be in your home for many years to come.
Cost of Repairing a Cracked Heat Exchanger
Totaling labor and parts, repairing a cracked heat exchanger can cost $2,500 or more depending on your furnace’s make and model. At the upper end, it could be above $5,000.
The math behind repairing vs. replacing your furnace becomes a lot more obvious when you see these figures, and is why a new furnace is often the better long-term choice for many homeowners.
Maintaining Your Heat Exchanger
The best advice for maintaining a heat exchanger is the same as it is for your entire system: make sure you’re getting regular tune-ups. Seriously, this adds years of life onto a heating system.
Related, keeping your filter up-to-date is important for airflow, which in turn allows the heat exchanger to do its job more easily. Wear and tear from a clogged system can take years off of your heat exchanger.
Next, make sure you have carbon monoxide detectors in your home that are functioning. This can be an early warning system if there are ever problems with the heat exchanger.
Last, make sure you’re working with a trusted HVAC contractor who can properly diagnose heat exchanger problems and provide you with a range of options if the need arises.
If you’re in the Sacramento area and are looking for that contractor, CABS Heating and Air Conditioning is waiting to hear from you. We’re excited to earn your business and keep it for years to come!
