Among new developed wireless local area network (WLAN) standards, IEEE 802.11n and 802.11ac are very important because these can support high data rates, are both new and widely used. Since the numbers of access points and users have been increasing tremendously, investigating the overall power consumption of these devices become an important research area. In this study, the power consumption of an access point, which supports both of these standards is measured with different values of transmission power levels and the number of active antennas. At the same time, data rates are recorded at the user side and the energy efficiency in terms of Joule/Bit is determined. The results show that, new systems which consume less power can be designed by taking into account these realistic measurement results and the energy efficiency values. Also, these results are the primary evidence which indicates that we can achieve huge gain in power consumption if new designs which enable to change physical layer parameters according to user data rate demands are taken place in future technologies.