An innovative renewable- energy based system is examined for covering the heating and cooling demand in residential buildings. This system adopts an alternative solar-assisted heat pump configuration, developed around its two main components: the PVT collectors and a dual-source heat pump. The heat produced by the collectors can be either used directly for covering the heating needs or stored in a buffer tank for supplying the heat pump with low-temperature heat, exploiting all solar heat and operating the heat pump with an elevated performance for a longer period during the day. Once the stored heat in the buffer tank is discharged, the heat pump is supplied by ambient heat. The same configuration can also operate at cooling mode during summer, with the heat pump reversing its operation. The current work examines the main system parameters, in order to evaluate its performance for covering a large share of the building's energy needs.