Hello @prestonjon Thanks for your comment and sorry for the late reply. First, I would like to clarify things as I am not sure that I understood your comment : the objective of this talk is/was not to point out a "more ecological" type of IoT device or saying that IoT is a necessary answer in the (environmental) challenges we are facing today. What we highlight here is the fact that IoT is often presented as a promising solution for optimization in many fields (smart cities, smart health, smart-everything, ...) BUT potential indirect rebound effects and direct environmental impacts generated over their life cycle (i.e. material extraction and refining, manufacturing, transport, use and disposal) are usually overlooked. We want to show that the (potential) benefits of introducing IoT does not come for free, and we motivate a more fair quantification of this balance. So far, this is very uncommon to find such analysis in IoT-related work (at least in academia, but I know that this is similar in the industry). The point of this talk (and the research behind it) was a first step in this direction. Further work is needed, that is for sure : and that is why we are trying to push that forward with more objective quantifications. The problem we want to address is consequently the environmental impacts of IoT devices, not only during the use-phase (related to energy efficiency as you mentioned) but over the whole life-cycle. Furthermore, we think that energy efficiency improvements must come together with sobriety if we want to have a chance to have net positive environmental impacts. This relates quite well with the question of "limits" that you mention also in your comment. Let me know if this is more clear this way ? I will make sure the message will be better expressed next time.