The usual objective of light weight refractory raw materials is to insulate furnaces in high temperature processes to allow a safe operation, with as little energy consumption at a maximum furnace capacity. A range of raw materials that are frequently used to formulate insulating bricks and castables are discussed in the first part of this review. In the second part, some special technical features of recently developed lightweight and weight-reduced refractory raw materials will be highlighted. They allow a valorisation in specific application areas beyond insulation and energy saving effects.