Human Centric Lighting? It’s about time!

by | Oct 22, 2020 | News

Good lighting design has traditionally been about making architectural spaces beautiful with minimum power density. That tradition of course will continue, but the element of time has become ever more important. Energy is, after all, the product of power and time. More significantly, lighting must vary with the time of day to ensure good sleep and thereby healthy building occupants.

Typically, time is a neglected tool of lighting design. Most architectural lighting designs think of time as static. But with circadian entrainment, it’s all about time. If you think about stage lighting there is a fixed person in the audience, and in each scene the lighting changes to reflect a new time. General lighting is the reverse. In real life you have static lighting and the people move. Time is an essential element in theater lighting, but usually not embraced in general lighting design. Why?

“Most architectural lighting designers think of time as static … but with circadian entrainment, it’s all about time.”

Light can be a way of articulating sequences to show the time of day or mood. Some circadian jobs are done in simplistic terms, with cool lighting in the morning and warm in the evening. Lighting can be a much more powerful dimension. A designer may need 300 lux on a horizontal surface and have to meet a certain watts/sq foot requirement. But the lights don’t always have to come from the ceiling. We will begin to see self-illuminous screens and perhaps and instead of a static watts/sq foot, what if the job consumed more power in the morning and less in the afternoon and could still meet the energy code?

Lighting should have more layers. Some open-air offices now offer Zoom Rooms where the employee will go to have great lighting for their online meeting. What if those horizontal lumens could be delivered at the desk, where the resources are? Employees should be able to quickly change the lighting to meet their specific task, and vertical illumination has to play a role. Designers seem to be stuck with ceiling lighting, and that is where the tonnage is, but I think that world is going to change.

I look forward to the time when time is a featured element of good lighting design.

This article originally appeared in the October 2020 issue of designing lighting.