HOW A HOT WATER COIL WORKS

Hot water coils are tube-fin heat exchangers made up of rows of tubes that pass through sheets of 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 allows for efficient heat exchange.

Hot water coils serve a wide range of applications, including energy recovery, reheating, preheating, booster heating, and comfort heating. They are commonly used in HVAC systems to regulate temperature and improve indoor air quality.

HOT WATER COIL DESIGN

While all hot water coils function similarly, their design and materials vary based on the application. Most standard coils use copper tubes with aluminum fins, though sizes can vary from 5/8", 1/2", or 3/8" in thickness. These coils can handle water temperatures up to 200°F.

In more corrosive environments—such as food processing facilities—stainless steel tubes or fins may be used to prevent degradation. Some coils also include headers, while others are referred to by different names like booster coil, reheat coil, or heater core coil.

The main purpose of a booster coil is to reheat air that has cooled during its journey through ductwork, ensuring warmth reaches distant parts of a building. In some cases, a collection header might be added, especially when replacing units like Heatcraft™/McQuay® coils.

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

SIZING A HOT WATER COIL

Replacing a hot water coil is often straightforward, especially when you need a precise fit. When measuring for a replacement, it’s important to check the fin height, fin length, and the number of rows. For new installations, we typically need the CFM (face velocity up to 1250 ft/m), entering dry bulb temperature, GPM (if available), and the desired leaving air temperature.

If you're taking your own measurements, our blank coil drawings page can help you accurately record the necessary details for a successful replacement.

ORDERING A HOT WATER COIL IS EASY

At Nationwide Coils, we offer a variety of custom options and select stock sizes to meet your commercial and industrial heating needs. Whether you need a replacement coil or a custom design, we’re here to help.

Feel free to email us with any questions or to request a quote on a hot water coil or any other replacement or custom coil. Our team is ready to assist you every step of the way.