Low-E glass can appear blue, green, or even slightly purple because of a microscopically thin metallic coating, commonly silver, applied to the glass surface. This coating reflects heat to improve energy efficiency, but it also reflects certain wavelengths of visible light. Under specific lighting conditions, such as direct sunlight hitting a shaded window, blue light is scattered more noticeably, creating a subtle tint or haze. This appearance is normal and is a natural result of the Low-E coating doing its job to control heat transfer and improve thermal performance.
Jan 21, 2026