A boiler is a container in which water is boiled or heated. Traditionally, boilers were made from boiler-plate, which is steel rolled into large flat plates. These steel containers were made and repaired by boiler-makers. The classic example of a boiler is the steam engine in which water is turned to steam to supply power to the engine. Today's boilers may be made from different material, but their principle use remains the same. They are used to supply either power, hot water, or heat in homes and buildings. Oil and electric boilers are available in hot water and steam, standard and high efficiency, and single or multiple models with either indoor or outdoor controls. For more information on boilers, talk with your service specialist.