August 27, 2025
Rising Murmurs: DLC’s New Rules Spark Lighting Debate
Critics demand balance between energy goals and quality, wellness-driven design
The DesignLights Consortium (DLC) is many things to the lighting industry: watchdog, threshold-setter, gatekeeper. Its technical requirements shape which products qualify for rebates, which make it onto specifications, and which quietly disappear from the market. That kind of influence ensures the DLC will never be universally loved. But in recent months, the murmur of discontent around its latest draft rules has grown louder.
On one side, manufacturers quietly tell us that proposed Version 6.0 raises efficacy thresholds to levels that are “extremely challenging, if not impossible” for some fixture types. They say so off the record, wary of jeopardizing relationships with the very group that decides whether their products get listed. On the Get a Grip on Lighting podcast, a recurring theme is that designing fixtures to meet DLC or DLC Premium standards sometimes runs counter to designing for what they call “quality light” — distribution, visual comfort and environmental-friendliness.
Into this atmosphere of whispered frustrations steps Dr. Martin Moore-Ede, who has taken the criticism public and loud. The Harvard-trained physician and longtime circadian researcher — who once sold his circadian lighting company to Korrus — has accused the DLC of sidelining human health. “The DLC wants to protect turtles, but not people,” he posted on LinkedIn earlier this week, turning what is usually a quiet technical debate into a pointed critique of how DLC standards dictate real-world lighting choices.
What Version 6.0 Proposes
The DLC’s Technical Requirements for LED Lighting: SSL V6.0 & LUNA V2.0 Draft 2 lays out updated thresholds designed to increase efficiency, improve controls utilization, and expand sustainability reporting.
In simple terms, it raises the bar: most products must hit between 125 and 145 lumens per watt, an average 14 percent increase over prior versions. DLC states that this will “provide the right amount of light for less energy.”
Above: Excerpt from proposed DLC Technical Requirements for LED Lighting: SSL V6.0 & LUNA V2.0
There are carve-outs. Turtle lighting, amber LEDs, 1800K and 2000K sources — all get special allowances and lower efficacy minimums. The DLC’s goal is to balance efficiency with ecological and specialty needs. But in Draft 2, there is no comparable recognition of “wellness lighting” designed for human circadian health, red-enriched spectra, or near-infrared output.
Moore-Ede’s Critique
Moore-Ede and a consortium of other stakeholders formalized their concerns in a 17-page draft letter to the DLC. “General Wellness Lighting Fixtures & Lamps cannot meet the proposed v6.0 standards,” they wrote, “because they are not designed to maximize the green and yellow wavelengths that determine visual brightness.” Instead, these products are tuned to regulate sleep, support metabolic processes, and mimic the spectral richness of sunlight.
The group urged the DLC to create a new product class with lower lumens-per-watt requirements — similar to a petition that was filed with the Department of Energy in 2023. Without it, they warn, schools, healthcare facilities, and workplaces could be locked out of incentives for human-centric lighting.
Moore-Ede’s criticism is sharper: by creating allowances for turtle vision but not for people, he argues, the DLC risks distorting the market away from human health.
The DLC’s Response
DLC CEO Christina Halfpenny acknowledged Moore-Ede’s comments but stressed that the organization’s doors are open. “The DLC welcomes feedback from all stakeholders on our SSL V6.0 and LUNA V2.0 Draft 2 Technical Requirements,” she said. “The formal way to provide feedback is to use our comment form and to email it to us by COB September 5.”
She also pushed back on the suggestion that the draft excludes non-white sources. “It should be noted that non-white light (NWL) LEDs, including 1800 K, 2000 K, pc-Amber, direct-emission Amber, and filtered Amber LEDs, are not limited to LUNA products (or even Turtle Lighting products). SSL V6 also allows NWL LEDs to be used for indoor and outdoor product types with technologically relevant thresholds.”
On controllability, Halfpenny pointed out that “nearly all indoor and outdoor DLC-qualified products must be continuously dimmable and report additional controllability information,” features that could dovetail with circadian and wellness goals. And critically, she left the door open to Moore-Ede’s request: “We also welcome proposals on new product categories with example data. Our organization is dedicated to integrity, collaboration, diversity, and impact, and appreciates receiving performance data from stakeholders, which can inform future product categories and product types.”
A Bigger Question
The dispute is not just about turtles or technical thresholds. It’s about how the industry defines “good” light or “quality” light. Should standards prioritize energy efficiency and rebate eligibility, or should they expand to explicitly include human health — even if that means lower efficacy?
For now, manufacturers grumble privately, podcasters take shots regularly, and Moore-Ede has gone public with a human-centric campaign. The DLC, meanwhile, is sticking to process: proposals through the comment form, data to support new categories, and a final set of rules expected in November.
The murmurs may or may not swell into actual policy revisions. For now, the industry sits with an unresolved dilemma: how to balance the drive for efficiency with the growing call for light quality and wellness-driven design.
