Energy management remains a critical problem in wireless networks since battery technology cannot keep up with rising communication expectations. Current approaches to energy conservation reduce the energy consumption of the wireless interface either for a given communication task or during idling. However, a complete solution requires min imizing the energy spent for both communication (i.e., for data and control overhead) and idling. This problem can be expressed as an energy-efficient network design problem, which is, not surprisingly, NP-hard. Therefore, in this paper, we study three heuristic approaches. Our study shows that the first approach that prioritizes communication energy conservation does not save energy. The second approach, which tries to reduce energy used for both data and in idling, becomes cost-prohibitive due to its high control overhead. Hence, we propose a third approach that prioritizes idling energy conservation. Due to its low control overhead, this approach meets the challenge of operating the network with low energy cost.