The results of the Light Right Consortium research study in Albany, NY found that occupant comfort increased by 15-20% with the use of indirect lighting, wallwashing and personal dimming control. Additionally, occupants with dimming control of their workstation-specific dimming control had increased motivation and were able to sustain their persistance and vigilance over time, as compared to those without any control of the lighting. Lighting systems that only provided downlight (2x4 troffers) were only rated as comfortable by only 69-71% of the respondents, leaving a significant percentage - 29-31% - uncomfortable. This finding was consistent with a normalized database, supporting the validity of the results. These results beg the question: are your office workers comfortable under their lighting?

The following recommendations provide a way to put the Light Right research results into action and increase the liklihood that your office workers are comfortable and satisfied. There are two "Recipes For Success."

TASK AMBIENT

The phrase "task/ambient" is meant to convey the separation between lighting systems that provide ambient (general) lighting throughout the office area and the lighting systems that are designed to increase lighting levels specifically at the task area. When there is uplighting to the ceiling and wallwashing for the walls, the perception of the occupants is that the space is bright and more spacious. The overall light level can be reduced slightly to 35 or 40 footcandles, as long as there is local lighting to supplement light levels at the workstation. When this is done energy is not wasted in the transition areas between and around the workstations.

Lights that are located under the storage bins are important with respect to reducing shadows that otherwise would create a dark surround on the inside of a workstation. The location and geometry of the undercabinet lighting varies-- in some cases it provides sufficient local task lighting as well as partition lighting, and in other cases it is necessary to provide a desktop moveable compact fluorescent task light that can be focused on the paper tasks. In many cases the wattage of the undercabinet light can be reduce to save energy.

Summary:

Provides room surface brightness using indirect pendant lighting fixtures. Light levels in the room can be slightly reduced when local task lighting is provided.

Study showed 10-16% improvement in occupant comfort.

Energy savings from fewer fixtures installed, newest component technology, and reduced ambient light levels.

Indirect-type fixtures are increasingly more available and affordable.

"INTELLIGENT" LIGHTING

The phrase "intelligent" lighting is meant to convey the use of advanced lighting control technologies. These control technologies include addressable digital ballasts that are located in the overhead lighting fixtures so they can be controlled by computer or handheld remote.
The energy savings benefits are dramatic, because many control strategies can be managed through one system for a typical combined savings of 60-80%. This is a progressive technology that requires additional up-front investment but yields exceptionally high value with respect to both energy and cost savings over time, and performance and comforts benefits for workers.

Important factors in the success of this type of system include: (1) workstation-specific overhead fixtures should be used, and the downlight component should not overlap to neighboring stations, (2) the uplight from the direct/indirect fixtures should be consistent across all fixtures, and not controllable by the user, (3) other lighting systems may be needed for the walls and transition areas, (4) commissioning is a critically important aspect of this system, and should be planned for in contract documents.

Summary:

Workstation-specific fixtures with constant indirect lighting and personally controlled downlight resulted in 20% improvement in occupant comfort.

Scientifically measured improvements in worker motivation and performance.

Dramatic energy savings from fewer fixtures, occupancy sensors, daylight dimming, peak load demand response, and personal control by the user.

Separate lighting systems are required for transition areas. Plan carefully to ensure proper commissioning and maintenance.