Will 2025 be the year when healthy lighting reaches the tipping point?
It depends on the key ingredients for change falling into place
When Malcolm Gladwell's book The Tipping Point was published in 2000, he brought attention to how small changes at a critical time can trigger an unstoppable momentum. However, the key ingredients need to be in place for a minor development to trigger a major change.
Over 99% of lights sold in 2024 were circadian unfriendly - that is they provided insufficient blue-rich light during the day and too much 440 - 495 nm blue content in the evening and at night.
So, what are the essential ingredients for change that must be in place for a revolution in healthy lighting to take place?
They fall into two categories - supply and demand.
Unless there is an adequate supply of the most common types of lighting fixtures and bulbs, then consumers won’t convert to circadian-friendly lighting. But, at the same time, there also needs to be a sufficient level of consumer demand for the manufacture and distribution of circadian-friendly lighting products to be commercially viable.
Supply Side
For commercial buildings, the most common types of lighting fixtures are Troffers ( square or rectangular ceiling fixtures), Linears (long narrow fixtures), and Downlights (typically 4-inch and 6-inch round ceiling lights). Only circadian-friendly Linears were available in 2024,
For residential spaces, downlights and light bulbs are most commonly used. These are either omnidirectional (e.g. classic A-19 or A21 light bulbs) or directional (e.g. BR-30 or BR-40 bulbs)
The supply in 2024 was largely limited to single-function light bulbs with a spectrum either suitable for daytime use, or for evening use. However, for circadian-friendly lighting to be widely adopted it needs to be dynamic - automatically switching between day and night modes.
New products being released in early 2025
Korrus (Ecosense) is adding troffers to their line of architectural dynamic circadian lighting fixtures. Like the linear Oxygen 1 & 2 and Nitrogen 1 & 2 architectural fixtures released in 2024, these automatically cycle between Max Blue day and Zero Blue night spectral recipes.
In addition, the Soraa division of Korrus is adding connected dynamic A-19 and BR-30 light bulbs that automatically cycle through four spectral recipes depending on the time of day. There is a MaxBlue spectrum, which delivers the >20% sky-blue light at the times required to sync the circadian clock, a museum blue-rich quality light for regular daytime use, a white zero blue light with violet for enhanced alertness in the early evening, and a 1400K orange light for winding down before going to sleep.
Removal of Regulatory Barriers: Petition to overturn the 125 Lumens per watt rule
Circadian lighting cannot reach the tipping point if the current regulatory barriers are in place. In 2023 the DOE enforced a 45 Lumens/Watt rule. which resulted in the banning of all incandescent and halogen light bulbs. Then in 2024 they upped the ante with a new 125 Lumens/Watt rule1 that becomes fully effective in 2028.
The 125 Lumens/Watt rule regulates lamps based on their “lumens per watt,” or luminous efficacy, which ignores the healthy (or unhealthy) properties of a light source. The DOE claims that the 125 Lumens/Watt rule promotes energy efficiency. However, this rule only regulates the energy efficiency of providing the green and yellow wavelengths that determine the brightness of light measured in lumens. The rule does not reflect the energy efficiency of delivering most of the light wavelengths that promote human health.
The watts of electricity required to generate healthy wavelengths of light outside the 500 - 600 nm green-yellow range are treated as wasted watts by the 125 Lumens/Watt rule. Thus, lights that are circadian-friendly (440-495 nm blue-rich day and blue-depleted night) or have a broader spectrum of healthy wavelengths outside the narrow 500 – 600 nm wavelength band that determines lumens cannot meet the 125 Lumens/Watt rule. The only lights that are favored and promoted by the 125 Lumens/Watt rule are blue-chip LEDs with a narrow artificial spectrum that is associated with ill health when used at night and does not provide adequately healthy light during the day
Whatever you think of the incoming Trump administration, their anti-regulatory stance offers the opportunity to overturn the US Department of Energy (DOE)’s 125 Lumens per Watt regulation that is stifling the development of healthy lighting.
So we are preparing a petition to challenge the 125 Lumens/Watt rule because of its enormous negative impact on human health and welfare. More details will follow in this Substack newsletter on how you can support this effort.
Demand Side
Educated consumer demand is essential for the widespread adoption of circadian-friendly lighting. If not enough people are sufficiently convinced of the health benefits to buy circadian friendly lighting, manufacturers will not make the investment to bring these products to market.
Increasing awareness of the excess disease burden of unhealthy indoor lighting
The evidence continues to mount for the rapidly increasing burden of chronic ill-health caused by unhealthy lighting at night and during the day. The total economic cost of the diseases influenced or exacerbated by blue-rich light at night is enormous. The Table below shows the total USA economic burden of these health disorders (from all causes, not just unhealthy light exposure). The incidence of each of these conditions is significantly impacted by insufficient daytime light and too much blue-rich light at night. Even a 1% increase in economic cost from unhealthy light exposure would create tens of billions of dollars in excess economic cost. And the adverse effects of circadian-unfriendly indoor lighting are much greater than that.
THE LIGHT DOCTOR Book
The scientific evidence is only useful if it is communicated and accessible to the general health-conscious public. That is why I made it a priority n 2024 to get my book THE LIGHT DOCTOR: Using Light to Boost Health, Improve Sleep, and Live Longer, published and to communicate its message in podcasts and interviews. It has been very gratifying to see the rapid month-on-month growth in sales of my book in the USA and internationally, since its publication in July 2024.
Buy a copy THE LIGHT DOCTOR and share copies with your friends and colleagues.
International scientific panels and commissions
Some international scientific panels were initially slow to acknowledge the health risks associated with the wrong light at the wrong time. However now they have started to issue warnings about the adverse health impact of using blue-rich light at night.
1. Scientific consensus that lighting should support circadian rhythms (2023)2
In 2023 a consensus survey of 248 of the leading circadian scientists, with a total of 2,697 peer-reviewed publications on light and circadian clocks since 2008, reached consensus on 24 statements, including:
There is now sufficient evidence to support the widespread introduction of circadian lighting that adjusts light intensity and blue content across day and night to maintain robust circadian entrainment and health.
Light used in the evening (during the three hours before bedtime) should have as little blue content as practically possible.
LED lights with high 460-495 nm blue content should carry the warning label “may be harmful if used at night.”
Increasing GSLs’ energy efficiency is desirable, but not if it increases the risks and resulting costs of causing circadian disruption and serious illness from other impacts to health beyond the benefits.
International Commission on Non-Ionizing Radiation Protection (ICNIRP) (2024)3
“Regarding disruption of the human circadian rhythm, we are still learning about this complex issue and ICNIRP is working on a related Statement to be published in the near future. In the meantime, as a precautionary measure, ICNIRP recommends that exposure in the evening or nighttime to light sources that are rich in blue light be avoided.”
3. U.S. National Toxicology Program (2021)4
“There is moderate confidence for a causal relationship between human cancer and certain lighting conditions — i.e., excessive LAN exposure combined with insufficient daylight exposure — that cause circadian disruption. This conclusion is based on strong evidence that LAN acts through mechanisms that are likely to cause cancer in humans.
• Toxicological and mechanistic data indicate that exposure to LAN causes melatonin suppression and other types of circadian disruption, which lead to the proliferation and growth of breast or mammary-gland cancer in experimental animals.
• LAN causes biological effects that are characteristics of recognized carcinogens.
• Studies in humans show that LAN causes melatonin suppression.
• The characteristics of electric light that are most likely to cause circadian disruption include a combination of short wavelengths (e.g., blue light), longer duration, exposure to electric light during the biological night, and higher light intensity or levels. The exact conditions (e.g., duration) depends on the combination of these metrics. In addition to exposure to electric LAN, total light exposure (e.g., insufficient exposure to daylight) is also important in circadian regulation and thus is part of certain lighting conditions”
4. International Energy Agency (IAE)5
"Measuring light with the usual photopic quantities, which are weighted by the V(λ) spectral luminous sensitivity function, does not give an accurate indication of the intensity of ipRGC exposures.”
"Given that it is well established that a healthy pattern of light and dark every day is necessary for good health, all lighting recommendations should reflect the need to deliver this pattern.”
Will the tipping point occur in 2025?
We can see the key ingredients for the initiation of explosive growth in circadian-friendly lighting are falling into place. But we will need to broaden our Campaign for Healthy Lighting to help trigger the Tipping Point. I urge you to sign up at https://circadianlight.org/campaign/
References and Footnotes
2024-04-19 Energy Conservation Program: Energy Conservation Standards for General Service Lamps (GSL); final rule ( abbreviated as125 Lumens/Watt rule). The actual minimum requirements for GSLs under this rule vary between 83.3 to 195.4 L/W (average 126 L/W) depending on the light bulb type, with the most common light bulbs having a 124.6 lumens per watt minimum.
Moore-Ede M, Blask DE, Cain SW, Heitmann A & Nelson RJ (2023) Lights should support circadian rhythms: evidence-based scientific consensus. Front. Photon 4:1272934 https://doi.org/10.3389/fphot.2023.1272934
International Commission on Non-Ionizing Radiation Protection (ICNIRP) https://www.icnirp.org/en/applications/led/index.html Archived December 27, 2024 at https://perma.cc/4YZN-3AWC
U.S. National Toxicology Program (2021). NTP Cancer Hazard Assessment Report on Night Shift Work and Light at Night; U.S Department of Health and Human Services, National Institute of Environmental Health Sciences: Research Triangle Park, NC, USA, 2021;
International Energy Agency (2024) Solid State Lighting: Review of Health Effects. https://www.iea-4e.org/wp-content/uploads/2024/10/SSL-Review-of-Health-Effects_Final-1.pdf Archived December 27, 2024 at https://perma.cc/T9Y2-7WJT
Absolutely tragic how they r systematically, methodically & slowly killing us - worse yet is that ppl don't know/understand/care. Thank u4being a Warrior👊
Thank you for your research and advocacy. I learn much from you including that which leaves me having some hope about systemic changes during my lifetime. I do like the idea of indoor lights that automatically adjust their output to better match our circadian needs!