The first essential step in daylighting is to design a building with maximum access to natural light through the use of open-air design, incorporating atriums, skylights, and windows to draw sunlight into workplaces. The second is to balance artificial light with sunlight to create optimal mood and functionality in the space.
Whether illuminating an office building, arts center, or educational facility, a fine method of control is needed to keep light levels balanced throughout the day and through different weather conditions. Lighting control systems can optimize lighting effects and provide the most efficient use of energy.
When incorporating a lighting control system, a daylighting strategy can be used to improve a building’s LEED rating in the following areas:
Energy & Atmosphere: Optimize energy performance, measurement, and verification
Daylighting has already proven to be an excellent strategy for increasing energy performance by eliminating the redundancy of artificial light when natural light is available just outside the windows. By configuring lighting ballasts for optimal supplemental lighting of low-light areas, entire sections of a building can rely on natural light throughout the day. Adding a lighting control system based on photosensors can improve the energy performance well above prerequisite standards and will reduce the building’s environmental impact regarding energy usage. A command center can continuously monitor light levels to track actual energy consumption, verify the building is meeting goals, and pinpoint trouble areas early.
Optimizing energy performance earns one to 10 points for new construction/major renovations and one point for commercial interiors. Measurement and verification earns one point in new construction and up to two points for commercial interiors.
Sustainable Sites: Reduce light pollution
A control system can be programmed to turn off or dim lights after sunset to minimize the impact of unnecessary lighting and reduce light pollution on the night sky. If a building requires night lighting, consider adding shades to eliminate light trespass and improve energy efficiency. Occupancy sensors can be used to ensure that light levels are increased for human safety as needed. Implementing light pollution reduction could earn one point for new construction/major renovations and one-half point for commercial interiors.
Indoor Environment Quality: Control systems, daylight, and views
Studies by the U.S. Green Building Council (USGBC) have clearly shown that employee satisfaction improves when people are given control of their lighting environment. Shades or blinds can help them control natural light, and lighting controls can help control artificial light at workstations. Personalized lighting control can be integrated into individual work spaces with control systems available at each user’s computer that tie back to the central command center. Studies have also shown that when users are given this flexibility the trend is to use lower levels of light than would have been assigned room-by-room. In new construction/major renovations this category earns one to two LEED points; commercial interiors can earn one to three points.
Daylight and views can be incorporated into a design to draw more light into the building in innovative ways that improve the lighting environment and the organic feel of a building. The more natural light that can be brought into high-use areas the more daylight can be harvested to reduce artificial lighting. In new construction/major renovations these effects can earn one to two points; for commercial interiors they can earn one to three points.
LEED-NC is the green building rating system for new construction and major renovations. LEED-CI is a benchmark for commercial interiors and sustainable building choices made by tenants and interior designers.
For more information on the LEED rating system, visit the U.S. Green Building Council’s website, www.usgbc.org, to download current documentation and find a directory of LEED-accredited professionals.