Home area network (HAN) consists of several wireless technologies and appliances that normally operate in the ISM 2.4-GHz band. This spectrum sharing environment can introduce interference problems and prevent peaceful coexistence especially for low power radio devices. Therefore, it is significant that these radio devices are spectrum agile as to avoid harmful interference and utilize the spectrum reliably. In this paper, the performance of a ZigBee Frequency Agile (FA) technique implemented on TelosB testbed is studied experimentally. The measurement results show that this technique can effectively overcome the interference caused by the Wi-Fi-based devices by changing the operating frequency of the ZigBee's FA-enabled testbed to the channel with the least interference level. In addition, the testbed with FA achieves throughput improvement by about 86%, reduces delay by 73% and enhances transmission energy efficiency by 64% as compared to the testbed without FA. Consequently, this proves that the FA mechanism can guarantee a seamless communication as well as incurring low transmission cost.