Re-thinking Daylight Metrics - IBPSA-USA Research Committee

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This recording is free to view for all. Note that the presentation starts at 7:15. The daylight metrics have been through lots of changes in the last decade. Such a change can be noticed in LEED daylight credit as it shies away from static metric (Daylight Factor, DF) to more dynamic ones (spatial Daylight Autonomy, sDA).  Although the modern daylight metrics offer some benefits compared to static metrics, a few disadvantages are embedded in the current dynamic metrics. As daylight availability seeks even distribution of daylight over time for the whole space, it is still confusing what metrics should be used for daylight availability or what threshold should be adopted for a specific daylight metric. This study tests a new hypothesis for daylight metric and offers a new statistical model to calculate daylight availability which presents an even distribution of daylight.

Learning Objectives: (Approved for 1 AIA Learning Unit)​

  1. Understand and describe Effective Daylight 
  2. Relate daylight quantity to daylight metrics including LEED metrics
  3. Put into context the disadvantaged of current daylight metrics
  4. Put into practice a new metric for daylight


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Our mission is to advance the sustainability of the world’s buildings through the use of integrated building performance modeling technology which more intelligently and assuredly determines the measures required to mitigate climate change and conserve our natural resources for future generations.


Sara Motamedi is a building scientist working as an energy and a daylight analyst at Interface Engineering. Her passion toward sustainable design motivated her to pursue a PhD degree with specialization in energy efficiency and daylighting strategies. She is interested in integrating different simulation tools and mathematical optimization algorithms to predict daylight and energy performance.