This paper describes final energy demand for different fuels at a disaggregated level of 12 activities of the economy plus households. The model used combines single equations for total final energy demand with translog functions for inter-fuel substitution. At both stages embodied and unembodied technical change is taken into account by a cost function with fixed inputs. At the stage of total energy demand this fixed input is the capital stock (where technology is embodied). At the stage of inter-fuel substitution the fixed inputs are non-fossil fuels (biomass, heat), which represent fossil-fuel saving or using technologies. Estimation results for the single equations and for the interfuel tanslog functions for the 13 activities are presented for Austria.