In this talk the current state of quantum thermochemistry will be analyzed with respect to its predictive potential for molecules of typical industrial engineering size. It will be shown that the recipes developed for small molecules can hardly be extended to molecular sizes of industrial interest, and that they even turn out to become partly invalid for larger molecules. Some viable protocols for larger molecules will be mentioned together with crude estimates of their accuracies and computational costs. Since most quantum thermochemistry methods so far are limited to the gasphase, while in industrial applications mostly fluid phases are relevant, some aspects of solvation for thermochemistry will be discussed.