Utilizing the solar and geothermal energy in space heating systems can save fossil fuels and reduce emissions. In this study, compound parabolic concentrator (CPC) photovoltaic/thermal collectors (PV/T), absorption and ground source heat pumps are integrated to a novel space heating system for use in hotel and office buildings. A full simulation model of the system is constructed and validated by using the Engineering Equation Solver software. The heating system is analyzed against its energy, environmental, economic, and flexibility performance using multiple variables including the PV coverage ratio, ambient temperature, solar beam irradiance, and electricity price. The results show that integrating solar and geothermal energy can be effective to supplement the space heating demand. The best integrated performance point of the office building gives a 32% energy saving ratio, 9% annual cost savings ratio, 23% emission reduction ratio, and 67% excess adjustable ratio compared to a pure ground heat pump system. This research provides new directions of integrated performance evaluation of heating systems assisted by renewable energy resources. (C) 2021 Elsevier Ltd. All rights reserved.