Data is provided to reconstruct the key figures (Figure 5, Figure 7, Figure 8 and Figure 9) of the paper “Optimization of heating curves for heat pumps in operation: outdoor temperature ranges for energy-efficient heating curve shifts”. Where Figures 7, 8 and 9 display simulated data of the study and were not directly measured. This data does not allow for a direct evaluation of the manufacturer or the heat pumps themselves, as the measurements and simulations were not designed as a controlled experiment. Potential measurement errors and uncertainties in the simulations have not been systematically validated.