Which daylighting strategies help tropical buildings maximize natural light while avoiding overheating?

• A. Direct sun through glass with no shading.
• B. Use diffused daylight, shading devices, light shelves, vertical louvers, reflective surfaces; avoid direct sun through glazing; clerestories with shading.
• C. Rely only on artificial lighting.
• D. Use only north-facing windows.

Answer: (B)

In tropical climates, daylighting aims to bring in as much natural light as possible while keeping heat and glare under control. The best approach combines turning direct sunlight into diffuse, evenly distributed light with smart shading and reflective strategies that prevent heat from entering.

Diffused daylight reduces glare and heat because it scatters light rather than letting strong sunbeams slam into interior surfaces. Shading devices block direct sun at the glazing, cutting down on heat gain while still permitting ample daylight. Light shelves push daylight deeper into the space by reflecting it off the ceiling, which also helps soften the light and reduce interior hotspots. Vertical louvers offer adjustable control of sun angles, especially during the hottest parts of the day, letting in daylight without letting in direct, heat-rich rays. Reflective interior surfaces boost the perceived brightness by bouncing light around the room, which means you can achieve good daylight levels with less artificial lighting.

Clerestories can bring in daylight from above, but they must be shaded to prevent direct solar gains from those high-angle sun paths. Together, these elements create a daylighting strategy that maintains visual comfort and brightness without overheating.

Direct sun through glazing, or relying solely on artificial lighting, would increase heat and glare or waste energy, and using only north-facing windows generally provides insufficient, poorly distributed daylight in the tropics.