A Look at Human Centric Lighting: Part 1

By Stan Walerczyk

Human Centric Lighting (HCL), which can also be called human factors in lighting, biophilia or other terms, is becoming the next big step in lighting. It may become more significant than Edison creating the light bulb, because not only can HCL provide good visual lighting quality, energy efficiency and sustainability at a reasonable cost, it can also improve circadian rhythms, short and long term alertness, sleep, mood, visual acuity, perception and performance–productivity. HCL provides both visual acuity and biologic benefits.

In addition to daylight, specialized fixed spectral content and tunable (dimming and Kelvin or color changing) LED products with advanced controls are already available and cost effective and should become standard for business, education, hospital, residential and most other applications much sooner than most people think. Within five years, and maybe as little as three, people will probably look back and wonder how they lived with that old lighting. Remember how it was before you had a smart phone!

Around the year 2000, internal photosensitive Retinal Ganglion Cells (ipRGCs) were discovered, LED started to be a useable light source, high scotopic/photopic (S/P) lighting which is typically high correlated color temperature (CCT) started to be used in retrofits mainly because visual acuity could be maintained while reducing wattage, and advanced controls were initially being developed.

Now there has been considerable neuroscience research on ipRGCs and the complete biologic part of vision, LED technology has greatly improved and is much less expensive, the Illuminating Engineering Society (IES) approved Technical Memorandum (TM)-24-13 which confirmed the visual benefits of high S/P lighting, and advanced wired and wireless controls have evolved and are becoming cost effective.

Some of the existing tunable LED products have about the same lumens, wattage, lumens per watt, rated life, warranty and cost as standard LED products, so why even consider standard LED products for most applications? The controls do add cost.

The wellbeing and performance–productivity benefits, which may be called ‘soft’ savings, usually dwarf the typical ‘hard’ savings of lower electrical bills, rebates and reduced maintenance costs. The soft savings can easily be $1000 per fixture per year for office workers, students and others. What is very important is that HCL provides both ‘hard’ and ‘soft’ savings. HCL shows the real value of lighting and makes lighting much more than a commodity, which is how most people have been considering it for decades.

So now is a perfect time for HCL, and it can be considered a wasted opportunity not to.

Here is just one example. In the 1990s, there was a study showing that baseball teams flying more than one hour time zone east gave up an average of one extra run per game. We installed tunable LED lighting in the Seattle Mariners’ home team locker room. The lighting is brighter with more blue content before night games so the players can be more alert when they go out to the field. After night games, the lighting has a lower light level and a warmer color tone to help the players relax and go to sleep later. The Mariners have a better record since this lighting was installed. Here is a video that explains the initial steps of the project:
http://planled.com/?portfolio=mariners-project-introduction

This lighting can also be very beneficial in offices, schools, hospitals, aged care facilities, manufacturing, etc. The second installment on HCL will include information on those applications.

Until then, you could check out the HCL website. I am chair of the HCL Society and Committee. We have some of the best neuroscientists and other experts in the world. The Society is a nonprofit organization. http://humancentriclighting.com/

My email is stan@lightingwizards.com, and I look forward to your ideas for future columns.