We propose in this paper a new Energy Efficient Interface Selection Mechanism that aims to reduce the energy consumption at multi-interface mobile terminals. Indeed, making the appropriate handover decision which at the same time fulfills the application requirements and reduces the energy consumption at the terminal could be a big challenge. The main idea in our solution is to consider the energy cost due to the handover procedure as well as data communication as the major parameter to make handover and interface selection decisions. We built our mechanism at the mobile node over the Media Independent Handover Function (MIHF) defined in the IEEE 802.21 standard. The overall architecture is based on a cross layer design and its performance is evaluated using comparative using NS2. The results have shown that our solution significantly reduces the energy consumption at the mobile node