Which combination of glazing and design features is effective for reducing heat gain and glare in large openings?

• A. Low-emissivity glazing only.
• B. Daylight controls only.
• C. Low-emissivity glazing, shading devices, reflective surfaces, and daylighting controls.
• D. Reflective surfaces only.

Answer: (C)

A balanced approach is needed: large openings gain comfort and performance when you both lower heat entering the space and manage the daylight that comes through them. Low-emissivity glazing reduces heat transfer by adding a coating that reflects infrared energy while still letting visible light through, which lowers the solar heat gain and improves insulation. Shading devices block direct sunlight at key angles, cutting peak solar heat and reducing harsh glare inside. Reflective surfaces help prevent heat buildup by bouncing radiant energy away from interior surfaces, rather than letting it be absorbed. Daylighting controls optimize the use of natural light, dimming or adjusting as needed to maintain comfortable brightness and minimize glare, while coordinating with shading to prevent over-illumination or contrast.

Put together, these features work in harmony to keep large openings cooler and more comfortable while maintaining good visual comfort. Using only one or two of these elements leaves gaps—heat can still enter or glare can remain—whereas the full combination addresses both issues effectively.