Taking a Closer Look at Replacement Hot Water Coils. (But not too close – they’re hot, folks.)

HOW A HOT WATER COIL WORKS

Hot water coils are tube-fin heat exchangers that consist of rows of tubes passing through formed fins, bonded through tube expansion. As cold air moves across the coil and touches the hot fin surface, heat is transferred from the hot water flowing through the tubes to the incoming air. This process enables efficient heat exchange.

Hot water coils are used in various applications, such as energy recovery, reheating, preheating, booster heating, and general comfort heating. Their versatility makes them a popular choice in both commercial and industrial settings.

HOT WATER COIL DESIGN

While all hot water coils operate on similar principles, their design and materials can vary depending on the application. Most standard coils feature copper tubes with aluminum fins, though other sizes like 5/8", 1/2", or 3/8" are also available. These coils can handle water temperatures up to 200°F.

In environments where corrosion is a concern—such as food processing facilities—stainless steel tubes or fins may be used for increased durability and longevity.

Some hot water coils are designed with or without headers. Without a header, they might be referred to as booster coils, reheat coils, or heater core coils. The main function of a booster coil is to reheat air that has cooled during its journey through ductwork, ensuring even heating throughout a building.

We’ve built countless custom and OEM replacement hot water coils over the years, ranging from small picture-frame-sized units to large wall-mounted systems. Many of these have been quality replacements for leading brands like Carrier®, Trane®, York®, and more.

SIZING A HOT WATER COIL

Sizing a hot water coil is relatively straightforward when replacing an existing unit. We measure the fin height, fin length, and count the number of rows. For new installations, we need additional details like CFM, entering dry bulb temperature, GPM (if available), and the desired leaving air temperature.

If you're taking your own measurements, check out our blank coil drawings page—it’s a great tool to help you record accurate dimensions and construction details.

ORDERING A HOT WATER COIL IS EASY

At Nationwide Coils, we offer a wide range of custom options and select stock sizes to meet all your commercial and industrial heating needs. Whether you need a replacement coil or a fully customized solution, we’ve got you covered.

Have questions or need a quote? Feel free to email us anytime. Our team of experts is here to make your job easier and ensure you get the right coil for your system.