The energy consumption of IT has a great impact on operational costs, in addition to being important for social responsibility and system scalability issues. Research on IT energy efficiency has always focused on hardware, whereas within the software domain it has mainly focused on embedded systems. In this paper we present the preliminary results of some experiments that we conducted to evaluate MIS applications from an energy efficiency point of view. We analyze in details some selected case studies, including 2 ERPs, 2 CRMs and 4 DBMS. Our evidence suggests i) that not only the infrastructural layers, but also the MIS applications layer does impact on the energy consumption; ii) that different MIS applications satisfying the same functional requirements consume significantly different amounts of energy; and iii) that in some scenarios energy efficiency cannot be increased simply by improving time performance.