Radiative Warming Glass for High-Latitude Cold Regions

Traditional window glazing, with inherently adverse energy-efficient optical properties, leads to colossal energy losses. Energy-saving glass requires a customized optical design for different climate zones. Compared with the widely researched radiative cooling technology which is preferable to be used in low-altitude hot regions; conversely in high-latitude cold regions, high solar transmittance (T_sol) and low mid-infrared thermal emissivity (ε_MIR) are the key characteristics of high-performance radiative warming window glass, while the current low-emissivity (low-e) glass is far from ideal. To address this issue, Drude's theory is used to numerically design a near-ideal film with specified electron density (n_e) and electron mobility (µ_e). The fabricated hydrogen-doped indium oxide (IHO) could achieve high T_sol (0.836) and low ε_MIR (0.117). Energy-saving simulations further reveal a substantial decrease in annual heating energy consumption up to 6.6% across high-latitude regions (climate zones 6 to 8), translating to a corresponding reduction in CO₂ emissions (20.0 kg m^-2), outperforming 1165 high performance commercial low-e glass. This radiative warming glass holds the promise of making a significant contribution to sustainable building energy savings specifically for high-latitude cold regions, advancing the goal of carbon neutrality.