What is the furnace coil, and what are things that can go wrong with it?
Split systems—combination HVAC setups that contain both heating (typically a furnace) and cooling (either an air conditioner or heat pump) components—have something unusual not found in ordinary furnaces: a furnace coil. But, just what is a furnace coil, and how do they work? In this article, we’ll explore this little-understood part and explain why it’s a big part of your split system’s performance—and why keeping it clean matters.
First, a quick note: if you need furnace or heating services here in Chicagoland, you’ll want to call the team here at King Heating, Cooling & Plumbing. Our techs know their way around all kinds of furnace setups and installs, and we can help address your maintenance, repair, and installation needs. We always recommend having us do a seasonal furnace tune-up in the fall to clean the furnace coil and other parts of your system.
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What exactly is the furnace coil?
This type of furnace coil is commonly known as an “A Coil” because of its distinctive shape.
Commonly known as “evaporator coils” or “A Coils” due to their distinctive triangular shape, furnace coils play an important role in your split system.
Air conditioners and heat pumps both work by moving heat from one location to another. For both systems in the summer, this means taking heat from inside the house and moving it outside. This is accomplished with refrigerant. As the refrigerant moves through the evaporator coil inside your home, it absorbs heat. That refrigerant then travels outside, where the heat is expelled and the refrigerant is then cooled, starting the cycle over again.
Heat pumps, of course, are able to reverse that operation in the winter, pulling heat energy from outdoor air (it might not seem like it on a cold Chicago night, but there’s some ambient heat energy there!) inside and expelling cold air.
Why is the evaporator coil installed with the furnace?
During the winter, as your furnace uses gas or electricity to generate heat energy, the furnace coil acts as a heat exchanger, absorbing that heat so that the blower can distribute it through your air ducts.
See an example of a dirty coil in this video:
Why is cleaning the coil so important?
Furnace coils are not only typically inside the furnace assembly, but may be in their own casing, as well. Most of the problems associated with dirty coils come from the lack of access homeowners have to clean them.
Dust and dirt
The buildup of dust and dirt can cause problems. Dirty furnace coils are not as good at transferring heat energy, and you’ll start to see your system’s energy-efficiency dip. In severe cases, extremely dirty coils can trap heat inside your furnace, causing the system to overheat and trigging temperature failsafes that shut off the system entirely.
Mold and mildew
When the air conditioner or heat pump is in use during the summer, the cold refrigerant stored in the heat exchanger, reacting with the warm air in your house, can cause the exterior to generate liquid condensate. This can lead to ideal conditions (warmth and water) for mold and mildew to develop. For obvious reasons, you’ll want to deal with this before it negatively impacts your indoor air quality.
Cleaning the furnace coil
As previously mentioned, it’s nearly impossible (and certainly not advisable!) for a homeowner to reach the furnace evaporator coil. The best time to get your coils cleaned is during your seasonal heating tune-up, which we recommend scheduling in the fall before the first truly cold days of winter. The earlier you book your tune-up, typically the easier it will be to schedule you in.
To make sure you stay on top of your furnace maintenance on an annual basis and avoid any problems, we recommend joining our maintenance program. Known as the King Royal Treatment Plan, this program includes regularly scheduled tune-ups and a number of other perks. Probably the best part of this plan is that we call you to schedule the service appointment. Nifty, right?
Why can’t I clean my own coils?
Beyond how difficult they are to access, we don’t recommend diving into your own furnace. You run the risk of voiding your manufacturer’s warranty when you open up your own system, and there’s always a chance that something can go wrong or get broken, making our 24/7 emergency repair a necessity. Worst case scenario, if not done right, you run the risk of harming yourself.
Honestly, take it from us: when you don’t have the right tools or the right training, it’s just not worth the trouble. It doesn’t even guarantee that your furnace will run any better!
This is just one of the home repairs you should never DIY!
Just like furnace coil cleaning, you should always call a professional to help you with risky or dangerous home projects. Check out our latest infographic to learn more!
Replacing the furnace coil
In the event that your furnace coil has stopped functioning altogether, you’ll need to have it replaced. The part you’ll need is dependent on your system’s manufacturer, the model, the system’s orientation, and more. For instance, Carrier—the brand King installs—has several types of coils, both in cases and out-of-cases. We recommend giving our team a call so that a technician can match you to the right part you need for your specific system.
Call King and get help from expert technicians
Our advice? Let our experts handle your furnace repair and maintenance—including cleaning your condenser coil. Contact King today for 24/7 repair.