Employ a layers of light approach which uses daylight for basic ambient light levels while providing occupants with additional lighting options to meet their needs. Set lighting goals (i.e., set a maximum Lighting Power Density goal and a daylight sufficiency goal) early in the project and craft a lighting strategy to achieve them. Utilize daylight harvesting best practices to supply ambient daylight to the space, and build upon this baseline with techniques and technologies to supply occupants with additional lighting options.
Large windows can provide daylight to interior spaces, but the daylight can be best used when complementary technologies are employed. Lighting controls can automatically turn off overhead lighting in response to sufficient daylight. Dimmers designed specifically for fluorescent or LED lighting can also be incorporated into this control scheme, providing a gradual transition between natural and artificial light throughout the day. Light shelves can help reflect light deeper into the interior of the space, making the best use of a window’s area. Exterior shading or overhangs can let more light in the space during the winter, when heat from the sun is needed, and block higher-angled light in the summer, decreasing cooling loads. Window coatings also have an impact on the amount and color of light entering your building. Occupants seated near windows may experience glare on computer monitors and be tempted to close blinds, cutting off daylight to those in the interior of the building. Provide these employees with glare-reducing filters for computer monitors so that use of blinds is reduced.