In machine listening there is a tendency to resort to models with a growing number of parameters raising thus concerns about the practical viability of these due to their energy consumption. Reporting energy consumption of the models could be a first step to raise awareness on this matter. Yet, estimating the energy consumption across different conditions (hyper-parameters, GPU types etc.) poses some challenges in terms of biases and fairness of the comparison between different models and works. In this paper we perform an extensive study using the DCASE task 4 baseline system and monitor energy consumption and training time for different GPU types and batch sizes. The goal is to identify which aspects can have an impact on the estimation of the energy consumption and should be normalized for a fair comparison across systems. Additionally, we propose an analysis of the relationship between the energy consumption and the sound event detection performance that calls into question our current way to evaluate systems.