This research investigates the energy efficiency of a novel double-glazing system incorporating solid-solid phase change materials (SSPCM), which offers significant advantages over the traditional liquid-solid phase change materials for thermal energy storage including no leakage, less phase-segregation, low subcooling, small volume variation, encapsulation-free implementation, extended durability upon thermal cycling, consistent optical properties, and reduced material degradation. Utilizing numerical simulations based on the finite volume method, a proposed double-glazing setup featuring a 2 mm layer of SSPCM applied to the inner glass pane within the air gap is analyzed. The simulations consider various transient temperature values of the SSPCM to evaluate the energy performance of the system under different weather conditions such as Montreal, Vancouver, and Miami during the coldest and hottest days of the year, both in sunny and cloudy conditions. During the summer, the system yields energy savings in Vancouver but leads to energy loss in Miami. In Montreal, however, the energy savings are only attained during sunny days. Conversely, in the winter, the energy savings occur across all climatic conditions only during cloudy days, with energy loss observed during sunny days. Furthermore, in cases where energy savings are observed, a higher transient temperature has also contributed to a more efficient system.