The Spatial Daylight Autonomy (sDA) index is an extremely important metric in architectural design, especially during the schematic design phase, as it helps guide many strategic decisions regarding building form, materials, and functional layout. Here's why sDA is so crucial:
🌞 1. Guiding Building Form and Spatial Layout sDA assesses the percentage of area within a space that receives sufficient daylight (e.g., ≥ 300 lux for at least 50% of the daytime occupied hours). During the schematic design phase, this index helps architects decide:
- Where and how large windows should be placed.
- Which facades need optimization for daylighting.
- Whether the building form should be recessed or protruded to enhance natural lighting efficiency.
🧠 2. Optimizing Energy Efficiency A design with a high sDA will reduce reliance on artificial lighting during the day → lowering electricity consumption. This can influence the design approach for lighting systems and electrical systems.
🪟 3. Supporting Material & Architectural Component Selection If sDA targets are not met, it may be necessary to consider:
- Changing glazing types (to higher transmittance).
- Adding solutions like sunscreens, skylights, etc.
- This helps avoid "fixes" in later stages, which can lead to increased costs.
📋 4. A Necessary Element for Green Building Certifications Many green building rating systems such as LEED, WELL, and EDGE require sDA reporting. If the project aims for these certifications, considering sDA right from the schematic design phase is mandatory.
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