A Study of Daylight Modeling Approaches Applied in LEED
Across various versions of USGBC Leadership in Energy and Environmental Design (LEED), the intent of the Daylight Credit has always been to connect building occupants with the outdoors and reduce the use of electrical lighting by introducing adequate daylight into the space. However, the credit requirements and assessment methods have evolved over time. The most recent version of LEED (v4.1) provides three options for assessing the Daylight Credit. The first two options are based on computer simulation, whereas the third relies on physical measurement. Option 1 performs annual simulation of “Spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE).” This research focuses on the first two options in order to assess whether their results are in line with each other, and to find out whether a space which contributes to points in one option would also contribute if the other option is applied, given that Option 1 and Option 2 adopt totally different approaches. To this end, an office space model, with dimensions of 30 feet × 30 feet × 10 feet and a WWR of 40%, was simulated under the conditions of Option 1 and Option 2. The simulations were run in 5 different cities, considering a variety of window orientations and two different interior shading devices as well as with and without an overhang. The findings of this study clearly show that significantly different results can happen between the two simulation approaches for quantifying the percentage of a space that is daylit for the purpose of evaluating LEED credits.
Advisors/Committee
