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System Impacts


Resources Impact

The lighting system has a tremendous impact on building resources, primarily through the electricity and associated energy it demands. Designing, implementing, and maintaining a lighting system that focuses on best practices for reducing the energy needed for proper indoor and outdoor illumination will have a considerable effect in achieving sustainability and reducing utility and operating costs.

By consuming 20% of the building’s total electricity consumption and further influencing overall energy demand by the waste heat it emits, lighting is a primary focus for achieving significant energy reductions, and therefore should be considered early in the building upgrade cycle.1

  • Effectively illuminate: Design according to the application of the space and the desired color, brightness, and ambiance. Avoid over-lighting by setting a Lighting Power Density goal. Limit the use of outdoor and accent lighting to only necessary applications and provide lighting controls such as occupancy sensors, timers, and dimmers for greater lighting control.
  • Optimize Daylighting: Set a daylight sufficiency goal and employ a daylighting strategy which utilizes a combination of windows, light shelves, and other external apertures such as skylights and light tubes to lessen the need for general electric light by distributing natural daylight throughout the building. Sensible furniture layout and color help to facilitate daylight reflectance. Locate workstations away from southern-facing windows to reduce the need for extensive shading, further allowing natural light to permeate. Find more daylight harvesting strategies here
  • Utilize high-efficiency technologies: Higher efficiency lighting such as fluorescent and LED use significantly less energy, have a longer lamp life, and an appropriate Color Rendering Index (CRI) while emitting a fraction of the waste heat as conventional incandescent lamps.
  • Ensure desired functionality: Educate occupants on the benefits and strategies for reducing electricity use, as well as the control systems in place to achieve energy reduction goals. Commission and retro-commission the lighting system to ensure proper functionality and maintained performance levels after implementation.

1. 2005 Buildings Energy Data Book

Choosing lamps and fixtures with long lives not only saves on maintenance costs but reduces waste that might otherwise go to the landfill. Fluorescent lamps are available in low mercury versions and LEDs contain no mercury, providing improved environmental benefits when compared to older products and technologies. You can learn more about LED performance, environmental impact, and life cycle energy consumption from these DOE studies

Green Tips and Strategies

Limit internal “night lighting” by utilizing occupancy sensors (currently allowed by safety codes) during off-peak hours. Reduce electrical lighting consumption and associated waste heat by pairing harvested daylight with automated dimmers and photosensors. Replace incandescent or other low efficiency light technology with higher efficiency alternatives like fluorescent or LED.
Limit the use of accent lighting. Couple necessary accent lighting applications with lighting controls to ensure highlighted objects are illuminated or illuminated at full power only when occupants are nearby. Avoid over-lighting by delivering the amount and quality of light necessary for the particular task. Employ a layers of light approach - using daylighting for basic ambient light levels while providing occupants with additional lighting options to meet their needs. Find more.
Allow optimal daylight penetration, orientating interior space layout accordingly. Utilize sub-meters to monitor electricity use and use this data to identify waste and maintenance concerns. Commission all lighting systems including controls to ensure they are performing as required and create a retro-commissioning to maintain the desired level of performance.