Heating coils are an important component of HVAC systems. They are used to transfer heat from one place to another, allowing the air in a home or building to be heated. The most common type of heating coil is an electric resistance coil, which is made up of metal wires that are heated when electricity is passed through them. This heat is then transferred to the air passing through the coil, allowing it to be heated. Heating coils are also available in gas and oil-fired varieties, which use a flame to heat the air passing through the coil. In addition to heating air, heating coils can also be used to heat water for hot water systems. Regardless of the type of heating coil used, they all work by transferring heat from one place to another, allowing the air in a home or building to be heated.