On the basis of a measuring-technical analysis taken, a computer-aided model for the energetic and economic evaluation of compressed air generating plants was developed. The model enables the analysis of an existing plant with the aid of generally known parameters and the new conception with an optimized layout, as well as the comparison of different staging of the compressors. The application of this model to a large-scale mechanical engineering enterprise resulted in halving the specific energy demand for the compressed air generation. The length of the amortization period of the total investment amounts to two years.