In the last decades, the energy consumption in wireless communication systems is increasing and becoming a major problem for cellular operators. As a result of that, solutions to increase energy-efficiency (EE) in wireless networks are becoming more popular. Therefore, the resource allocation algorithms that provides EE for multiuser OFDM based wireless networks is presented in this paper. Then, the conventional spectrum-efficient (SE) designs are compared with EE based schemes and EE characteristics of the system has been analyzed. The simulation results show the advantages of EE scheme especially on high channel-gain-to-noise ratio and low number of users cases.