Decarbonisation is one of the most important challenges facing researchers, and solar-assisted systems represent an important solution to reduce the energy consumption at the household-scale. The current work contributes to existing research by proposing and validating a novel lumped parameter simulation model for photovoltaic thermal hybrid solar collectors using field measurements carried out at an experimental facility. The modelling approach, which also considers the effect of the thermal capacitances of the elements composing the photovoltaic thermal collector, used an electrical analogy method to solve the transient heat transfer problem. The results of the simulations were compared with the experimental data collected during different weather conditions; the effects of the thermal capacitances of the collector were also investigated. The results were compared in terms of both average daily performance and instantaneous values of the variables characterizing the system. Although the differences were negligible, the results of the simulation analyses matched the measurements more precisely when the thermal capacitances were taken into consideration. Finally, the simulation model was implemented as a TYPE of Transient System Simulation (TRNSYS) software, and it is made freely available to facilitate future integrated computer simulations.