Abstract-Evaluating the energy efficiency of software applications currently is an ad-hoc affair, since no practical and widely applicable model exists for this purpose. The need for such an evaluation model is pressing given the sharp increase in energy demand generated by the ICT industry. In particular, we need to get in control of our software applications since they play a key role in driving the consumption of energy. This paper proposes ME 3 SA, a Model for Evaluating the Energy Efficiency of Software Applications. ME 3 SA provides a practical breakdown of energy efficiency into measurements that can be applied to software applications in relation to the quantity of work they deliver. This approach makes it possible to measure and control energy efficiency similar to other software qualities such as performance efficiency or maintainability.Furthermore, we report on a case study in which the model was applied to an operational software system of the Software Improvement Group (SIG), a software advisory firm based in the Netherlands. The case study provides evidence that the proposed model is able to identify energy consumption hotspots and efficiency bottlenecks within software applications.