In this demo we present Joule, a software enabling real-time power consumption monitoring of networking devices without having to deploy physical meters in the form of, for example, managed Power-Over-Ethernet supplies. We will demonstrate how Joule can estimate the power consumption of commercial WiFi Access Points by exploiting observable network statistics and under different workloads, e.g. browsing, video streaming, and background FTP traffic. An interactive web dashboard will allow attendees to have a first hand experience on the correlation between traffic and power consumption.