In January 2025, the Department of Energy published three guides to adopting LED lighting and controls in school buildings, augmenting the resources available through its Efficient and Healthy Schools program. One evaluates a particularly interesting nonenergy benefit of LED lighting realized through controls: the ability to adjust color. Authored by the Pacific Northwest National Laboratory (PNNL), “Why Tunable? A Look at Schools” examines the impact of tunable-white LED lighting installed at eight school districts between 2015 and 2023.

LED lighting offers various advantages that resulted in widespread adoption, notably its energy efficiency, longevity, compact size and inherent controllability relative to traditional sources. An additional novel capability, however, is the ability to adjust color output in addition to intensity to support visual needs.

Traditionally, light source color was more or less fixed after installation, with the simplest solution to replace the lamps. In contrast, LED technology offers the potential for dynamic color output with general lighting. By separately dimming LED arrays with a different correlated color temperature (CCT), a range of warm to cool shades of white light can be produced as well as saturated colors if other colors are added to the mix.

Tunable-white lighting’s advantages

Why is this important? Tunable-white lighting has many applications, allowing CCT to be adjusted based on changing space use and user preference. In schools, some educators are drawn to this capability as a means to cue students for activity changes and desired behaviors (e.g., quiet down or focus attention). It can also be particularly useful for supporting students with disabilities.

The study represents new construction and upgrades in existing buildings. The researchers were interested in why these schools opted to install tunable-white lighting, what features they chose, how the solutions were implemented and what teachers thought about it.

Schools installed tunable-white lighting for a range of reasons, including energy savings and increased familiarity with LED technology, improving lighting quality by controlling color and intensity (dimming), and supporting teachers and students.

Teachers could adjust the lighting to support various learning activities and communicate activity transitions. Typically, a teacher will cue students by ringing a bell or talking loudly. With tunable-white lighting, the transition from one shade of white light to another provides an effective visual cue. This proved particularly interesting for classrooms for students with special needs, where teachers could most benefit from tools for cueing desired behaviors.

A wide range of solutions were installed. The majority of installed systems provided a range of CCTs from around 2,700K to 6,500K, available through the interface as preset CCT levels or, in some cases, selectable anywhere on the CCT range. One school opted for an 1,800K to 8,000K range, and another installed full-color tuning, with any shade of white light plus saturated colors available.

Similarly, the control interfaces varied to include switches, buttons, sliders, touchscreens and phone apps, with preset or customizable options in addition to continuous dimming for intensity control. In one project, a rooftop sensor was installed to dynamically adjust interior lighting color output to the daylight cycle.

Overall, teachers like having tunable-white lighting as a tool. The field evaluations yielded interesting feedback. According to the report, “Teachers responded positively to the tunable lighting systems in their classrooms, indicating the lighting improved the working and learning environment for themselves and their students.”

Generally, teachers found the use of adjusting the lighting an effective cue, with a net gain in desired behaviors and the presets being helpful for speed and convenience. Some also found the control an interesting point of student engagement, as students would request various settings or offer to help adjust the lighting themselves.

At two schools, PNNL analyzed lighting control data showing how the systems were used day to day. Lighting intensity was adjusted more often than color, with teachers independently valuing this capability.

Regarding downsides, one school reported the control could be distracting for students wishing to use it themselves. When asked what they would change, control methods were frequently cited, with one school wishing for simpler control options and another asking for a handheld remote.

These PNNL field evaluations highlight tunable-white lighting as an attractive tool for the education sector, an upgrade option for existing LED adopters that prioritizes value beyond energy savings and a possible starting point for converting a school building to LED lighting. 

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