Hydronic coils are an essential component of any hydronic heating system. They are a type of heat exchanger that transfers heat from a hot fluid to a cold fluid, usually through a metal coil. The hot fluid is usually water or a water-based solution, while the cold fluid is usually air. The hydronic coil is typically located in the ductwork of a home or commercial building, and is responsible for heating the air that is circulated throughout the building. Hydronic coils are often used in combination with other heating systems, such as a furnace, to provide an efficient and cost-effective heating solution. Hydronic coils are also used in cooling systems, where they transfer heat from a cold fluid to a hot fluid. The hot fluid is usually a refrigerant, while the cold fluid is usually air. Hydronic coils are an effective way to transfer heat from one fluid to another, and are an essential component of any hydronic heating or cooling system.