Supplementary data for the IEEE Transactions on Power Systems article "Modelling heat pump systems in low-carbon energy systems with significant cross-sectoral integration" by Philipp Härtel and Debraj Ghosh (Fraunhofer IEE) Contains the case study power system time-series result data for Germany in a net-neutral energy scenario, i.e. four different heat pump system modelling approaches: detailed, lumped, aggregated without COP correction, and aggregated with COP correction Contains heat pump system input data, i.e. heat demands for space heat, domestic hot water heat, and corresponding COP profiles, as well as lumped and aggregated versions based on the proposed methodology in the paper.