A hot water coil heater is a type of heating system that utilizes hot water to provide warmth to a space. It works by circulating hot water through a series of coils that are connected to a heat source. The heat source could be a boiler, furnace, or other heat source. The hot water is then circulated through the coils, which absorb the heat and transfer it to the air in the space. This type of heating system is efficient and cost-effective, as it does not require a large amount of energy to operate. Additionally, hot water coil heaters are often used in commercial and industrial applications, as they are able to provide large amounts of heat in a short amount of time. Hot water coil heaters are also often used in residential applications, as they are able to provide a comfortable and efficient way to heat a home.