Curtain walls contribute to sustainability through several key features. They often use high-performance glass and framing systems that enhance energy efficiency by maximizing natural light and minimizing heat loss or gain. Sustainable curtain walls are designed with low-emissivity coatings and insulated glazing to improve thermal performance and reduce heating and cooling demands. Additionally, modern curtain walls can be integrated with shading systems and photovoltaic panels to further enhance energy efficiency and reduce the building's carbon footprint. Using recyclable materials and incorporating environmental design principles also contribute to the overall sustainability of curtain wall systems, supporting green building certifications and reducing environmental impact.