One of the most important issues in wireless sensor networks (WSN) is reduction of power consumption, prolonging the network lifetime (for battery powered networks) or reducing the induced CO 2 emissions (for grid powered networks). Power consumption reduction can be achieved in various ways: transmitter power control, duty cycling, data reduction and others. This paper analyses the impact of several parameters on power consumption of Digi's XBee PRO of shelf WSN modules. To determine the conditions for transmitter power control, this paper presents measurement analysis for indoor RF propagation in order to determine the minimum received signal strength for high data transfer reliability. Measurement analysis is conducted using response surface methodology and the conclusions based on the respective measurement results are given resulting in a mathematical model of the node's power consumption. Also, optimization of power consumption is shown for various parameters using desirability functions, where optimal parameters for minimum power consumption are presented.