Wireless Sensor Network (WSN) is a promising technology and due to itsmultitude applications such as remote monitoring, personal medical monitoringand home automation, it has become one of the most interesting tasksin the recent years.A WSN consists of many sensor nodes which sense physical phenomenaor collect data from an environment.Depending on a predefined application of a network, sensor nodes canbe located in fixed places or distributed randomly over a large geographicalarea. Their communication with each other occurs wireless and they share achannel for signal transmission. Some parameters such as position, distance,power consumption for each node and communication technology betweensensor nodes have inevitable impact over the network’s performance.In spite of a tremendous development, there are still limitations thatWSNs suffer. Some challenges like designing a low power network, data securityand architecture of network have taken the most attention of researchersin the last years.The energy consumption is one of the most common problems in thewireless sensor network that does not appear in more traditional wired sensornetwork. Each sensor node is battery operated and it makes a wireless sensornetwork highly depended on each node battery. It is very important topredict the lifetime of a wireless sensor network before network installation.Our work will be based on analysis of a communication protocol (ZigBee)when the network forms Star and Mesh topologies.The monitor of greenhouse condition is the main concept in our work.The temperature will be measured with sensor nodes, and the sensed datawill sent to a remote center. We are looking for the best and most suitabletopology in term of low power consumption for this scenario.