This paper addresses the polytype target coverage problem for heterogeneous wireless sensor networks (HWSNs) with clustered configurations. This problem is formulated as an integer programming (IP) problem for maximizing the whole lifetime of HWSNs. We present an energy-efficient target coverage algorithm (ETCA) to solve this problem and balance the energy consumption of sensor nodes. Each sensor node first calculates its sensing capability with neighbors' and sends a message with its current status information to a clusterhead. Then, the clusterhead decides which sensing units should be turned on to cover the targets in the most optimized way based on the information received from all its member nodes. Simulation results show that the performance of ETCA is close to the IP-solution that is an optimal coverage scheme regarding the energy efficiency. Moreover, ETCA can prolong 16% network lifetime compared with the energy first (EF) algorithm.