The article deals with the technical possibilities and economical operating facts of rational energy consumption. Beginning with a short discussion of the available energy reserves it is shown that a rational way of dealing with energy can already be pre-programmed in the choice of the energy form for each particular consumption purpose. Economic growth, indeed, promotes the rational use of energy. The following main points are individually discussed: related subjects in economic pre-planning operation, energy economy in the heating of houses, questions of environmental protection. The article ends with a look at future aspects of rational energy utilization.