This article conducts study on the performance evaluation of two configurations of a solar-powered two-stage humidification-dehumidification (HDH) desalination system using a parabolic trough collector (PTC). The system includes the simultaneous heating of both air and seawater (feedwater), aiming in heat and mass transfer enhancement and improving overall productivity. A thermodynamic model was developed to simulate the behavior of the system under different operating conditions, including heat transfer fluid (HTF) flow rates, feedwater temperature, and salinity. Configuration I employed air heating before the first stage, while Configuration II introduced air heating between the two stages. Main findings reveal that Configuration II achieved superior performance over Configuration I, with a maximum freshwater productivity of 70 kg/h and a gain output ratio (GOR) of 0.88, whereas it was 50 kg/h and a GOR of 0.84 in Configuration I. The study also shows the influence of air characteristics and feedwater parameters on system efficiency, enlightening the optimal design strategies for solar-driven HDH desalination units. These results demonstrate the potential of dual-heating configurations to improve the feasibility of sustainable water production in arid regions.