An investigation of alternative daylight metrics

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Summary

This research challenges the traditional use of working-plane-based daylight metrics (such as daylight factor) in modern buildings, proposing an MRSE-derived metric that better captures the spatial quality of daylight as perceived by occupants. For lighting designers, the findings suggest that metrics accounting for ambient and omnidirectional light distribution may more accurately reflect real-world daylight adequacy than horizontal illuminance alone.

Key Findings

Traditional daylight factor metrics focused on the working plane may not adequately represent daylight quality in modern spaces where room appearance and occupant perception are prioritized.
An MRSE-derived daylight metric was proposed and evaluated as a potentially superior predictor of user perceptions of daylight adequacy compared to existing working-plane-based metrics such as Daylight Autonomy (DA) and Useful Daylight Illuminance (UDI).
Climate-based daylight modeling metrics (DA, UDI) were identified as gaining significant interest as alternatives to traditional daylight factor approaches.

Categories

The Science of Light: Investigates alternative daylight metrics including MRSE, cubic illuminance, and cylindrical illuminance as replacements for traditional working-plane-based daylight factor metrics.

Workplace Performance: Examines how daylight metrics relate to user perceptions of adequacy in modern indoor environments where task performance and room appearance are prioritized.