Combined solar and heat pump systems have a large potential to reduce CO2 and other emissions from the sector of domestic hot water preparation and space heating. Subtask C of the IEA SHC Task 44 / HPP Annex 38 deals with modeling and simulation of these systems. A review of component models for the simulation of combined solar and heat pump heating systems has been carried out with a special focus on the particularities of the combination of solar thermal collectors with heat pumps. Some of these particularities are effects of water vapor condensation on the surface of collector absorbers operated below the dew point, refrigeration cycles using more than one heat exchanger for the evaporator in order to use solar heat in addition to a conventional heat source, the effect of higher source temperature for the heat pump when solar heat is used, or the regeneration of ground heat sources with heat from solar collectors.