Daylighting is a center-stage issue for commercial facade design. It's recently been a much- discussed topic within the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 90.1 - Energy Standard for Buildings except Low-Rise Residential Buildings Envelope Subcommittee. It is a priority issue for the skylights industry. New glazing options with impressive light-to-solar-gain ratios open up new possibilities. Studies quantifying the benefits of daylight and views for student performance have spurred architects to advance the design of day lit schools. This document discusses some of the key elements of daylighting. This document was published in July 2012, and updated in 2019.