Energy aware routing protocols are consistently cited as efficient solutions for ad hoc and sensor networks routing and data management. However, there is not a consistent approach to define the energy related cost metrics that are used to guide the routing protocol performance. This paper provides a survey and analysis of energy related metrics used for ad hoc routing. First, the most common energy efficient routing protocols are classified into four categories based on the energy cost metrics employed. Then, the results of our simulation-based analysis are presented. We conducted a complete set of simulations to compare and contrast the performance of various energy-related metrics. Our analysis provides a comparison of the performance of energy cost metrics used within AODV-based ad hoc routing protocols.