The cumulative production energy input of a product comprises all the necessary energy inputs for its production, starting with the winning of the raw materials right up to the end assembly and delivery. For the determination of the cumulative energy input, the process chain analysis was applied in most investigations, which, however, leads frequently to a systematic underestimation of the cumulative energy input. As an alternative or addition, respectively, the energetic input-output analysis is at one＇s disposal. In the following, a modified form of this method is described, with which, apart from the cumulative energy inputs, also the cumulative CO2-emissions can be determined quickly, whereby distortions of earlier investigations are excluded.