What are the key thermal performance metrics to specify for a glass curtain wall in high-rise buildings?

When specifying the thermal performance of a glass curtain wall for high-rise buildings, B2B buyers and architects must evaluate several critical metrics that directly affect long-term energy efficiency, occupant comfort, and compliance with global building standards. The most important metric is the U-value, which measures heat transfer through the glazing and framing assembly. Lower U-values indicate better insulation performance, which is essential for reducing HVAC loads in tall commercial structures. Another critical metric is the Solar Heat Gain Coefficient (SHGC), especially for buildings in warm regions such as the Middle East, Southeast Asia, and southern United States. A lower SHGC helps minimize solar heat penetration, reducing cooling demand. Visible Light Transmittance (VLT) must also be optimized to balance natural daylight with glare control. Thermal breaks within aluminum frames, inert gas fills between glazing layers, and low-E coatings all contribute to stronger performance. Engineers also assess condensation resistance and local climate conditions when selecting the right specification. Together, these metrics ensure that the glass curtain wall supports long-term operational efficiency, maximizes environmental comfort, and meets increasingly strict energy regulations.