Common Ground High School

The lighting design for the new multipurpose building for this environmental charter school is a teachable example of the school’s commitment to sustainable design.

One of the school’s most visible sustainable design strategies is the integration of abundant natural light with highly efficient and daylight-responsive electric lighting.

Windows, clerestories, and skylights are woven into the timber fabric to make daylight the predominate source of daytime illumination in the classrooms, circulation areas, and assembly spaces. Careful attention to siting, orientation, massing, transmissivity, and shading helped the design team to optimize daylight quality, cross-checked with computer modeling.

The electric lighting design evolved in response to the daylight directionality and availability to provide supplemental illumination during daytime. During the evening, the building is a glowing lantern inviting visitors to after-hour events and gatherings. Intuitive dimming controls in classrooms and the gymnasium/auditorium provide needed variability. Automatic occupancy- and daylight-responsive controls ensure that unneeded light is turned down or off.

This project achieved LEED-NC 2009 v3 Gold certification including all credits for daylighting and views, lighting controls, and 19 energy points plus one point for exemplary performance based on 61% energy cost savings. This is partially attributable to a lighting power density of 0.85 W/sf or more than 25% below the ASHRAE Standard 90.1 baseline for schools. The combination of daylight and high-quality electric lighting contributes to student attention and circadian health.