Documenting the Potential Benefits of Tunable LED Classroom Lighting

The final results are in for a DOE GATEWAY evaluation of a trial installation of tunable-white LED lighting systems in three classrooms at an elementary school in Folsom, California. Pacific Northwest National Laboratory evaluated the energy and photometric performance of the adaptive systems to explore energy-saving potential. The evaluation found that if both systems are operated at full output, the LED system would provide 46% annual energy savings over the incumbent fluorescent system, while producing similar illuminances.

Image (left) and reflected ceiling plan (right) of the classrooms L1 and L2 with the installed LED lighting system.

BACK TO SCHOOL

The tunable LED lighting system was installed in August 2017, just before the start of the Folsom School District’s school year. One of the three classrooms was used for general-education fifth-graders and the other two for ASD students. In each classroom, existing two-lamp T8 fluorescent recessed luminaires were replaced with recessed 2′ x 2′ white-tunable LED luminaires, and one 12′ white-tunable LED wall wash surface-mounted luminaire was installed above the whiteboard.

A wall-mounted, touch-sensitive controller, which communicated with the luminaires via a DMX512 protocol, was installed next to the whiteboard and offered five preset scenes that could be altered with dimming (0%-100%) and color-tuning (2700 K to 6500K) slider bars, in addition to featuring on/off power buttons for the entire system and for the general and whiteboard luminaires separately.

Tunable lighting systems offer the potential for significant energy savings relative to fluorescent systems and non-dimmable LED lighting systems. These savings are attributed to the higher efficacy of LED systems versus comparable fluorescent systems, and the dimming capability provided by tunable lighting – with additional energy savings possible in schools where illuminances exceed Illuminating Engineering Society recommendations.

Lighting energy use for a 24 hour period in Classroom L2.

ENERGY SAVINGS

Collection of energy data began during the last week of the 2016-2017 school year, while all three classrooms were operating under fluorescent lighting systems, and continued through the 2017-2018 school year. Based on the monitored energy use, the actual savings during a typical day ranged from 48% to 69%, depending on how the teacher used the controls.

 ADDITIONAL BENEFITS

The trial LED lighting installation at FCUSD not only offered significant energy savings compared to the incumbent fluorescent system but ultimately provided teachers with an additional tool for facilitating classroom activities. The implementation of the lighting system varied between classrooms, but the teachers included in this study agreed that the LED lighting system offered an improved working environment for themselves and the students.

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