<p>The enhancement of photoelectric-thermal conversion efficiency of solar energy holds considerable promise for achieving substantial energy savings and emission reductions in the domain of residential heating and electricity supply. This paper proposed a novel approach for converting a photovoltaic system into a roll-bond panel-based photovoltaic thermal (PVT) heat pump system capable of concurrently generating electricity and domestic hot water. A test rig was constructed to assess its comprehensive cogeneration performance. The results demonstrated significant cogeneration capabilities, with an average electrical efficiency of 19.66%, an average heat gain factor of 0.89, and an average heating performance coefficient of 5.15 under specified weather conditions. The heating performance coefficient of this system was 12% higher than the designated first-class energy efficiency rating (4.60) for air-source heat pump water heaters. Controlled experiments were also conducted to evaluate the systematic electrical output compared to the photovoltaic system with an identical electrical subsystem configuration. A considerable decrease in PVT module temperature was witnessed, resulting in an enhancement of electrical production by 4.4% during the test period. Furthermore, a mathematical model was developed and validated by the experimental outcomes. The systematic annual cogeneration performance and the potential for CO₂ emissions reduction were also assessed. The simulated annual average heating performance coefficient and the electrical output improvement were 4.90 and 3.67%, respectively. In light of this, annual CO₂ emissions of the proposed system were calculated to be 192.3 kg CO₂, representing a reduction of 91.1% compared to the emissions from the pathways of natural gas-fired power and gas water heater heating.</p>