Induction heating is much used in combination with other sources of energy. The decisive factor frequently is that desired results in the melting and heating of ferrous and non-ferrous metals can be attained. The article presents a review of technical and economic data which can be achieved in the melting and holding of ferrous and non-ferrous stock through the combined use of fuel and electricity as sources of heat. Some applications are described. The savings in energy and operating costs obtainable in comparison with electricity as sole source of heat are shown in graphs.