In this paper, the physical layer of the Wi-Fi IEEE 802.11ac standard is analyzed from the energy efficiency point of view. To better assess the energy footprint of Wi-Fi communications, the power dissipate d in the circuits to run the signal processing algor ithms is taken into account in addition to the classical transmission power at the antenna. Simulations and hardware developments on a Field-Programmable Gate Array board provide a reliable evaluati on of the power distribution between transmitter and receiver components. This evaluation enables an identification of the most consuming components, and an analysis of the impact of system parameters on power consumption.