Models and proposals for capturing the energy consumption of sensor nodes are plentiful. The majority of those approaches roughly agree about the energy consumed in the states of the sensor node duty cycle, but the costs of radio operations are abstracted very differently. In our work, we establish a general framework whose modular structure allows to compare existing abstractions and to investigate which factors are crucial for the modeling of transmission costs. We analyze the influence of typical assumptions on the creation of energy efficient routing topologies. For this purpose the resulting routing trees are not only compared by topological characteristics, but also by estimating radio related energy consumptions, a metric which changes strongly with the MAC layer efficiency.