The best way to conserve energy in wireless sensor networks is to change the radio interface state to sleep mode. The sensors in sleep mode conserve energy, whereas the sensors in active mode use their energy to continue to monitor the target. How sensors are scheduled between active and sleep modes affects the lifetime of the sensor network. Some existing scheduling schemes do not achieve maximum energy efficiency because they do not take into account both overlapping target coverage and the residual energy of sensors. It is important to reduce overlapping target coverage because it can waste sensor energy unnecessarily. In this paper, we propose a new energy efficient algorithm that takes into account both overlapping target coverage and the residual energy of sensors. Simulation results show that this algorithm produces more number of cover sets than the existing algorithms, so that the network lifetime becomes higher.