—Multi-technology wireless networks enable the combination of the strength and usage of different wireless systems such as Wi-Fi, mobile and IoT networks. The design of such networks requires primarily the study of the radio coverage of wireless technologies that, most of the time, operate in different frequency bands. For this purpose, this paper presents a multi-wall and multi-frequency indoor path loss model based on measurements performed from 800 MHz to 6 GHz in the same residential environment. The presented results are focused on the carrier frequency effect and on the level of details of the building representation. Index Terms—path loss, multi-wall model, residential environment.