Today's world is facing numerous problems due to an uncontrolled waste of energy and of primary resources in general. To manage this, on one side designers are asked to improve the efficiency of products; on the other side, users must be trained toward a more sustainable lifestyle. Some researchers are exploring the idea of trying to change users' behavior while interacting with products in order to make it more sustainable. This trend is known as "design for sustainable behavior" applied to energy/resources consumption issues. Our idea is to stimulate users in changing their behavior by introducing a multisensory communication with the product. This communication is not meant as warning messages informing the users about wrong habits/actions or something like; instead, it should consist of sensorial stimuli able to naturally drive users in performing the right actions. However, before designing these stimuli, it is fundamental to highlight the aspects and conditions that do not allow users behaving in a sustainable way when interacting with products. In this paper we discuss about the aspects that could be useful to explore in order to retrieve the specifications to drive both the design and prototyping phases, so as to faithfully test the effectiveness of the feedback with final users.