The Real Reasons to Specifying Tunable White

When tunable white light debuted a few years ago there was a lot of discussion about how and when to specify it. The most justifiable reason people could come up with was to stimulate circadian rhythm. Research remains somewhat conflicted (I’ll get into more takes on circadian lighting soon) since most research on the topic can be refuted by counter research it leaves specifiers with no reason to fight for it on the spec, especially in the age of instant VE.

There are real reasons to specify tunable white that have nothing to do with circadian stimulus. Tunable white is a tool lighting designers should be deploying more often because it will make jobs easier and lighting designs more dynamic.

Integrated LED fixtures all share a basic strength and weakness. Because the LEDs are integral to fixture, changing anything about them is nearly impossible most of the time. There are certainly downlights with changeable modules, but specifying an LED slot or wall grazer your color is an fixed choice.

This compromise relies on certain CCTs having to be “good enough.” The common palette provided by chip manufacturers is 2700, 3000, 3500, 4000, 5000. That menu of options is pretty good. But it isn’t *all* the white light tones on the spectrum.

Tunable white gives designers the capability of calling up 3250K or simply shifting the color warmer or cooler based on the needs to the space as it’s seen in real time.

We all know that 3000K means different things to different manufacturers. A Cree 3000K chip is going to look different than a Xicato 3000K. A 4” slot with Nichia 3500K chips is going to look different than it’s neighboring downlight with Cree LEDs. These variations are unavoidable and only become more pronounced when lenses and filter media are introduced.

Matching tones of a given CCT on a project is nearly impossible. But specifying tunable white allows you to visually match the tone of the light, or more accurately, the experienced tone of the light right in the space in real time.

This could mean matching tones of white light, or it could mean finding complimentary tones. It depends on the project and the desired effect (of course). Where this becomes really interesting is in crafting effects that might shift over time.

There’s been lots of discussion about how to use tunable white light to stimulate circadian response. Maybe it’s the theatrical designer in me, but I’m much more interested in how tunable white could transform a space over time.

The sketches above show the same space with a simple inversion of the lighting tone. The table top and surrounding walls simply trade warm and cool light. This simple inversion radically transforms the space.

Imagine this kind of transformation in a lobby, or a restaurant or a hotel room. Tunable white offers designers the possibility of painting with tones of white light hand selected in real time.

You did your due diligence with the interior designer. He brought in the wood grain laminate samples and you played with different CCTs. The 2700K sample looks great. The correct fixtures were ordered, they even got installed properly. Then the plastic protection comes off the wood paneling. It looks a lot more brown than anyone remembers...damn. How did this happen? Who knows? Maybe it got an extra coat of stain at the factory. Maybe this run of wood was a bit darker, maybe the red carpet is reflecting back on the wood. Either way, it’s a problem because moving from 2700K to 3000K means an expensive fixture replacement.

Tunable White light solves the oops factor. While it’s always best to test and mock-up treatments, the real world has ways of surprising us. In the scenario I describe above, the design team is stuck. Now imagine if TW had been specified? A few taps on the keypad and the fixtures shift from 2700K up to 2900K and the redness is muted slightly. The dining room looks great.

Tunable white isn’t a panacea. There are real reasons it doesn’t make it onto jobs. The most glaring of these is cost. We live in the age of instant value engineering and upfront cost analysis is inevitable. When viewed as a luxury item, tunable white is the first thing go. The challenge here is to shift the mindset from luxury item to essential. One could argue lighting design at all is a luxury. My argument is advanced tools like tunable white light can add infinite value to the lighting design system and are worth the initial investment. In short, variable white light available instantaneously is a game changer. To not consider it in future specifications would be like not considering dimming.

Control system complexity

I get this one, I do. Controls are already deemed too confusing. There are multiple ways to get to tunable white control. If I had my way, instead of settling on 0-10v control as the default we would have decided that DMX was the best way to control LEDs. DMX can be done simply and relatively inexpensively, if it is planned properly at the outset. LEDs mean digital dimming and control. Pulling 0-10v wire or daisy chaining DMX cable shouldn’t inherently make that much of a difference.

I’m withholding judgment on smart systems like PoE and DALI ever making mass market infiltration. They might 🤷🏻‍♂️ but until they do, it’s hard to call them the answer. That said a system like power over Ethernet could conceivably deliver all power and data in a simple CAT6 cable. Whether or not that comes to fruition remains to be seen, but it’s possible.

End User Training / Long Term Use

One argument against advanced lighting solutions like tunable white is that they have to used by end users who have no interest in playing with the color of their light in their spaces. I actually don’t know that to be the case. I think we tell ourselves that story because it fits our narrative that only “lighting people care about lighting”

Once end users understand the capabilities of the light in their space they will be much more likely to appreciate and actually use the technology.

There’s another aspect to this that I think is subtle but interesting. Tenant fit out spaces are often done and redone defaulting to building standards for fixtures and color temperatures. If those systems and standards included tunable white, they would have to be redone less often.

Most major manufacturers today offer tunable white options in nearly every form factor imaginable. It’s time to play with and specify tunable white.

Need help? Let me know.