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Polycarbonate (PC) glazing as a one-for-one glass replacement offers a 50% weight reduction, but exhibits several dB lower sound transmission loss (STL) in the low frequency range where tire and engine noise are dominant. In the high frequency range where wind noise is dominant, PC glazing offers an STL at least comparable to its glass counterpart, and an STL exceeding glass when this frequency range encompasses the glass coincidence frequency. However, a key value proposition of PC glazing is the opportunity for feature integration afforded by the injection molding process generally used for forming such glazing. Two-component (2K) molding fuses a second shot of plastic material behind, and along the perimeter of, the transparent PC first shot. This second shot can incorporate features and implement functions that require additional components attached or peripheral to a glass version.

Reduced battery discharge rates in electric vehicles (EV) tend to extend single-cycle range as well as battery lifetime. Vehicle features that tend to reduce battery discharge rate thus support viability of EV. Of special interest are features that reduce the load on the heating, ventilation and air conditioning (HVAC) system since that system can in turn impose a significant load on EV batteries. A companion paper quantifies the effect on steady state nominal HVAC load of glazing (i.e. window) thermal conductivity using Computational Fluid Dynamics (CFD) to simulate heat transfer between the ambient and the air in a model car cabin when the cabin air is maintained at a comfortable temperature. For hot and cold climate, and for stationary and moving cars, reductions in HVAC load resulted from replacing a monolithic glass backlite and rooflite with polycarbonate (PC), the latter with a five-fold lower inherent thermal conductivity.