From GridLAB-D Wiki
window_wall_ratio – Ratio of window area to wall area.
Synopsis
module residential; class house { double window_wall_ratio[pu]; } object house { window_wall_ratio value unit; }
Remarks
The window_wall_ratio is expressed as a percentage of the total wall area. It used to determine the value for window_area.
Default
The default window_wall_ratio is 0.15.