IEEE 802.15.4 networks are promising solutions for wireless personal area networks, and in particular for wireless home area networks. IEEE 802.15.4 has numerous applications in fields such as energy management and home automation. However, real-world trials with 802.15.4 devices are difficult because of the characteristics of these devices (small dimensions, wireless communication), and the potentially large size of the network. We present in this paper an IEEE 802.15.4 network emulation testbed that makes possible repeatable and controllable live experiments with 802.15.4-based devices. The testbed is built by extending the functionality of the wireless network emulation testbed named QOMB with 802.15.4 PHY and MAC layer capabilities, as well as 802.15.4 device processor emulation. We illustrate the usability of the 802.15.4 network emulation testbed with a case study of home networking used for automation related to environment control.