Tunable White & Circadian lighting
Interview with Jeff Hungarter, Commercial Indoor Director, Cree Lighting, on the topic of tunable-white lighting, focusing on its potential intersection with circadian health.
Craig DiLouie: How would you characterize demand for tunable-white lighting?
Hungarter: The demand tunable white is just starting to climb the curve for being specified and driven into lighting projects. There is lots of interest and education going on, but we still see many times it’s the first item “Value Engineered” out when budgets get tight. Across many verticals, they like the idea, but don’t want to pay for it.
DiLouie: How would you characterize demand for circadian-friendly lighting designs? Has the COVID pandemic spurred more interest in wellness and lighting’s role in it?
Hungarter: Lots of interests and questions about circadian lighting design, but I would not say we have seen a spike in demand for these types of products. COVID has spun more interest in disinfectant lighting than Circadian or tunable white lighting by far. The market is struggling to keep customers, patients, and students safe, so naturally they are gravitating to the “assumed” benefits of what disinfectant lighting can provide, but we should use caution in understanding the tradeoffs of these varying solutions.
DiLouie: What role does color spectrum specifically play in circadian regulation?
Hungarter: Color spectrum plays a big role in Circadian regulation, but not the only one. Entrainment also requires a balanced combination of the correct luminous intensity, distribution, and duration of light, among other variables, to have a meaningful impact.
DiLouie: What is the full functionality that tunable-white luminaires offer to support circadian lighting designs?
Hungarter: As mentioned above, tunable white systems need to be able to support not just changing color spectrum, but also have the ability to dynamically change in intensity and duration during the day. We must also take into account the amount of light that is getting to the eye which is critical, so light distribution of the fixture also plays a role.
mood, satisfaction, and well-being?
Hungarter: Well, if implemented correctly, tunable white solutions can enhance people’s moods by giving them a touchstone to the outside world, especially in places where they have no access to windows or sunlight. In combination with other design elements like ergonomic furniture and enhanced air quality can really influence the well-being of the people in the space.
DiLouie: A challenge of plugging tunable-white lighting into a circadian design is that circadian stimulation may be more closely related to spectral profile than CCT. Do you agree this is an issue, and if so, how is your company and the industry in general addressing it to adapt the technology to circadian lighting?
Hungarter: I think the industry is still learning a lot about circadian lighting design and how it affects people differently. In our Cadiant Dynamic Skylight, while we designed to mimic the spectral content of a natural day, the software behind it is flexible so as we learn more about what is needed for circadian lighting we can adapt our fixture to meet those needs.
DiLouie: Currently, there are two specifications for circadian lighting, one promoted by UL/LRC and the other by the WELL Building Standard. What are the metrics these use, and how do they primarily differ? What do they offer the industry?
Hungarter: There are lots of discussions in the lighting design world about the various measuring metrics. Both have the starting base that multiple photoreceptors in the eyes send signals which can trigger varying responses. While they may differ in “the how”, the research and development of these and other studies all help bring attention and education of how important light and other design elements can support health and well-being.
DiLouie: What is the impact tunable-white lighting can have on adherence to these requirements?
Hungarter: Tunable white lighting can play a large role to help meet the standards as we learn more about the benefits and educate ourselves to “do no harm”. We’ve heard many a lighting designer say, “I don’t want to prescribe light, I’m not a doctor”, so we must be careful here if we are attempting a true circadian design and bring in those who understand the science of health and well-being.
DiLouie: How does circadian lighting in general and tunable-white lighting installations in particular differ from typical lighting designs, and what can distributors do to support the process to ensure good outcomes?
Hungarter: In many typical lighting designs, you may be just replacing an existing fixture and have limited ability to change much of the design layout. With tunable white and circadian lighting designs, you would want to make sure the design is well thought out and factors like the range of color spectrum, amount of light able to get to the eye, and how the light distribution patterns and intensity change throughout the day are accounted for, to just name a few.
DiLouie: If you could tell the entire electrical industry just one thing about tunable-white lighting’s role in circadian lighting, what would it be?
Hungarter: Don’t be fooled, tunable white lighting is not circadian lighting. Tunable white will/can play an integral role as we gain more research and learn about where circadian lighting is going, but research and education are going to be key as we drive health and well-being into current and future lighting designs.