Scaling of average Poynting flux ⟨S_z⟩ with unsigned surface flux Φ and average coronal heating ⟨H_tot⟩. Each data point represents an average for one of the model runs with different unsigned surface magnetic flux as listed in Table 1. As a reference for the magnetic flux, Φ_ref, we choose the magnetic flux of the least active setup, run 1B (cf. Table 1). The bars represent the standard deviation of S_z in time. The red lines are power-law fits to the data. See Sects. 5 and 6.1.