Depletion of natural resources and the growing energy usage for air conditioning in buildings necessitate energy-efficient window technologies that minimize power consumption and ultraviolet (UV) exposure, especially in the UV-A region. Herein, we report a silver-free hybrid nanocomposite coating composed of cesium-doped tungsten oxide nanoparticles (CWO NPs) and metal-free carbon dots (CDs) for simultaneous solar heat and UV-A shielding. The incorporation of CDs induces aggregation of CWO NPs, converting a dense NP film into a highly porous CWO-CD film that enhances solar absorption and scattering. By tuning film thickness and morphology, the CWO-CD coatings achieved 85% UV-A blocking and 92% near-infrared shielding. Comparative tests using a laboratory-scale miniature house model under constant solar illumination revealed that the coated glass exhibited lowered temperatures by 12 °C compared to an uncoated glass. This work introduces a silver-free, hybrid nanocomposite as an energy-saving coating for window and skylight applications.