Category: Technical Lighting Help

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Technical Lighting Help

The Complex “Cost of Electricity” Data

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Recently, my LinkedIn feed has been filled with conversations about the cost of electricity, likely due to the noticeable surge in price. Most include a graphic and many include dated or erroneous/suspicious information. I don’t think people are being malicious, this is a complex topic and the supportive data is equally fraught with confusion.

Energy vs. Electricity

When a point is being made about energy consumption that does not necessarily mean electricity. If you look at the US energy Information Administration (EIA,) energy is defined as electricity, natural gas and heating oil and propane. Some statistics even include the cost of gasoline and diesel fuel because it is energy we consume. Even more broadly, we could include the cost of coal, hydropower, solar, wind, geothermal, biomass, ethanol and uranium because they are used in the creation of electricity. None of these are wrong observations, but what information is right for a viable assessment of cost and cost savings?

As lighting people, we can’t really impact home heating and gasoline has little bearing on watts consumed to illuminate a space. The cost of coal, hydro or nuclear power are baked into our price per kilowatt-hour of electricity. That said, it might be easy for us to home in on the price of electricity, but that too, is complex.

The Different Prices for Electricity

Electric companies across the United States sell electricity at different rates to different entities. There are residential, commercial, transportation and manufacturing rates. There is also a combined average. If you are like me and have spent a career concentration on residential lighting, the residential price per kilowatt-hour is all that you need. Commercial lighting people will need the commercial and industrial (manufacturing) numbers to help aid in justifications.

States, Regions and National

Data is collected across states; states are accumulated into regions and a national average is finally calculated. All those numbers are made available and by themselves, are correct. So which do you use?

It is important to note that the price of electricity varies wildly across the nation. Hawaii is always the highest in the country, the Northeast corridor typically makes up the remainder of the “Top10” with Alaska and California also in that top ranking. The least expensive electricity seems to change each year from the bottom ten states. That means the national average should be considered just that, an average.

2024 Stats

(A note, about EIA stats. Yearly numbers take a few months to accumulate. The 2025 averages will likely be published sometime mid-year to the third quarter. For that reason, most people will be using the 2024 number for the next few months.)

The average price for electricity to the ultimate residential customer in 2024 was 16.48¢/kWh. For the commercial businesses, 12.75¢/kWh, Industry paid 8.13¢/kWh and the transportation sector price was also12.75¢/kWh. Across all four sectors, the average was 12.94¢/kWh.

https://www.eia.gov/electricity/annual/table.php?t=epa_02_04.html

To understand the wide variation of prices, the EIA breaks the data down. In 2024, Hawaii, of course had the most expensive residential electricity in the nation at 42.86¢/kWh and North Dakota enjoyed the least expensive electric cost of 11.51¢/kWh, almost four times less. The commercial, industrial and transportation sectors, by and large, fall into similar proportional rankings.

https://www.eia.gov/electricity/annual/table.php?t=epa_02_10.html

Hawaii is the most expensive because it is an island-state. It must generate all of its electricity on the islands. Buying or selling excess production is not possible, hence the high prices. Alaska also finds itself in the same position for the same reason. Within the contiguous United States, high prices are borne by densely populated areas and low prices are enjoyed in sparsely populated states. For that reason, California, New England states and New York comprise the list of the most expensive contiguous states.

The cheapest electric rates have a few anomalies. Washington is always on the list, because of the large amount of hydro generated power. Tennessee is also a constant primarily because of the TVA. The other states have smaller and more rural population, in general.

Twenty Years

I have been talking about electrical consumption for over twenty years. To help designers, lighting professionals and consumers understand the benefits of energy efficient lighting, first fluorescent, then LED, I talked about the long-term or lifecycle cost of lighting. To give people a better understanding of the financial reality, we looked at first cost PLUS the cost of electricity over the lifespan of the luminaire, knowing full well, electricity would increase.

When I first started delivering talks on lighting energy consumption, the 2004 national average cost of electricity was 8.95¢ per kWh. That means the average cost of residential electricity has increased 84.8% in twenty years! Has your salary increased 84% in that time? If not, more of your discretionary dollars are being used for non-discretionary needs.

As I began my research, I remember reading that electric cost had not really experiences huge jumps in the decades prior to 2004. Later, listening to a speech given by the CEO of ComEd, I learned that those rates were stable primarily because the market was continuing to grow. In the early 2000s, growth was difficult and even impossible. Fewer households were being formed, it was getting very difficult, almost impossible to build a new power plant and because of age, the power infrastructure was in dire need of replacement. She promised at the time, “Rates will/must go up.” Today, we are hearing that electric rates are rising primarily because of the massive draw required by data companies to facilitate Artificial Intelligence (AI.) To undertake this massive level of computer processing a lot of electricity is used. What’s more, it takes a lot of electricity in a country where almost no added electric creation is being built. No new output with substantial new demand and only limited ways to increase efficiency do not make for a good future. The short prognosis must be, rapidly increasing electric rates. Aren’t you glad the federal government cancelled all those wind and solar energy creation initiatives? (Sarcasm implied.)

But there is one more wrinkle, PUCs. Public Utility Commissions regulate the electric rates for regions and states. Because they are political organizations they may be resistance to increase rates commensurate with demand and reality. If that becomes the case, then expect electric reliability to fade. When the money is not available, maintenance is the first thing to suffer. Our 100 year old electrical infrastructure is in poor health. Things will break. Users have a horrible choice ahead of us, pay more for electricity or assume outages as a typical way of life. Sorry for the Sophie’s Choice, but this also explains the increased introduction of resilient lighting product.

I’m actually very pessimistic as we enter the second quarter of this century. America was finally looking at energy creation alternatives, but the Luddite community persevered. Even if we make substantial changes to our government makeup, progressive initiatives do not just restart in an instant. All this occurred while China continues to decommission coal power plants and increase non-fossil fuel alternatives. We could quickly enter a time with rapidly increased electric cost for a supply that is unreliable. I’m not sure I like that prognosis.

PS: To my Canadian friends and readers, SORRY, I have not done twenty years of research on Canadian rates, but I do know that Canadian utility companies have been far more proactive than US concerns. Hopefully you’re not in the same boat!

If you want the best information available on energy, check out the US federal government’s excellent resource, The Energy Information Administration:

https://www.eia.gov/

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Technical Lighting Help

The Health Cost of Energy Efficiency

Since I have spent time trying to understand the health implications of light, I have read scores of scientific reports on the subject. The work of Dr. Mariana Figueiro is of course very central and most people in the lighting industry have had the privilege to read and listen to her talk about practical solutions for light and health. The name that comes up second is Dr. Martin Moore-Ede. He has probably been a louder voice with a perceived higher level of worry about the new LED and how they interact with human health.

His most recent realm of concern has been aimed at how LED manufacturers achieve more (and more) efficient LED light sources. He believes that the newer LED are eliminating output in specific color ranges to achieve the required efficacy. By so doing, the human body is not receiving enough light to satiate the demand of certain opsins in our body.

As you know, I’m not a doctor. Lord help us if indeed that were the case, so I’ll try to explain this as simply as I can, one lighting person to another. If you’re a doctor or a scientist, please stop here and read another blog post!

You, me and all other humans have a series of opsins in our body. These opsins are receptors in our eye’s photoreceptors that detect light in their various wavelengths and responds in some sort of predetermined physiological way. For example, Opsin #1 provides us with color vision and Opsin #2 allows us to see in minimal light and the dark. Most every LED works fine delivering light in this wavelength range.

Opsins #3, #4 and #5 are non-visual opsins. Receiving light in their required wavelength aid in human health. If an inadequate amount of light is delivered in these wavelengths, human health suffers. The correct amount of light at 480nm drives our circadian cycle, thanks to the work of Opsin #4. Opsin #3 requires light at 430nm and Opsin #5 requires a wavelength of 380nm. All three help regulate glucose levels, energy and retinal refraction. The increase in myopia (nearsightedness) is linked to reduced levels of the violet-rich (380nm) light needed by Opsin #5.

Light at the far-right end of the visible spectrum, moving into infrared light is likewise important for human health. This light, peaking at 825nm, is not detected by opsins because it has the ability to penetrate deeply into the skin. Proper amounts of light in this range have shown to improve blood flow, skin health and assorted healing properties.

Imagine you are a caveman or an early farmer, living off the land with no electric light. Much of your life is spent outside, planting, foraging, playing or cleaning. Daylight naturally delivers light in the full spectrum. The body receives an ample quantity in each wavelength, for each purpose. Skip ahead to today where children play inside and adults work in an indoor office or factory. To get the proper amount of light in the proper wavelength we must rely on artificial light.

Full spectrum LED lighting can provide light across all wavelengths, thereby delivering all the light needed for human health. As efficacy requirements are raised and consumers demanded less expensive options, manufactures have built LED that produces light across a narrower band of light. Most of the lumen measurement is concentrated in the green-yellow range (500nm-600nm.) While less expensive, they fail to provide the lower and higher wavelengths needed by these opsins and our skin.

Where Does That Leave Consumers?

The easiest answer is, “Spend more time outside!” Of course, that is somewhat impractical in today’s world. Your second option should then be natural light indoors. Place work desks near windows, prevent light inhibition, avoid using fenestration materials that filter out light wavelengths (if you have the option) and as a last resort, buy better lighting.

The color spectrum of natural light stretching across the area visible to humans

This is an image of the color spectrum of natural light across the area visible to humans. (380nm to 750nm) Ultraviolet light would be off the chart, on the left and infrared light is situated off the chart, on the right. While there are some peaks in the blue area, most of the colors are equally and evenly delivered.

If selecting artificial daytime light, you want to look at a spectrum diagram of the light and select one that is as close to this as possible. It is important to know that artificial daytime light should ONLY be used during the day. We need great light during the day and minimal levels of warm/red light at night. Using full spectrum light at night might have an adverse impact on our circadian system. Again, go back to our analogy of a pre-electricity farmer. Even on a great day, the sun did not shine for 24 hours. Think of a full spectrum light as a replacement for sun, not a light bulb. (Some full spectrum LED is available with a nighttime mode that removes the blue, thus creating a warmer evening illumination.)

Remember too, Full Spectrum lighting is NOT the same as Daylighting. Most daylight LED is simply 5000K to 6500K and not likely to be spread across the full spectrum. Full spectrum lights do not have to be 5000K or 6500K, but might.

One more thing. The sun is very bright. Light bulbs are not the same as the sun. You can get the right color of light from a lamp, but not the same amount. Think of full spectrum artificial light as a supplement to the sun, not a replacement.

I hope this has helped a bit. This remains a complicated issue. We are hoping artificial light can alter lifestyle changes. Perhaps it can help, but it is unlikely to replace the body’s need for sunlight. When possible, get outdoors, plant some flowers, drag the laptop onto the patio when you’re working and do your homework on a lawn chair. Your body will thank you…and you’ll sleep better, too.

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Technical Lighting Help

Is Home Automation a “Time-Saver?”

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My wife and I have just moved into our new-old home. We have spent almost a year restoring and reinvigorating a mid-century ranch that will deliver a more carefree (and step-free) life for us as we age. Because of the rough state of the home when we purchased it, a rewire was required. Many walls were removed (black mold) the ceilings were taken out (water ingression from a leaky roof) and fuse boxes removed (Federal Pacific Electric Panel.) The lack of physical encumbrances made the lighting choices easier. I could spec almost everything I wanted and the wiring part would be easy. (Well, easier. Doing so within the confines of maintaining the mid-century characteristic of the home soon became the hindrance.)

I decided to install a Control 4 Home Automation system to “run” the house. Security, lighting, garage door, shading controls, temperature control and intercom could fall under one umbrella. The Bosch appliances, themselves supported by a proprietary app could be brought into the group. There are other functions that could be integrated as well. Luckily, I have been using a local tech-guru that helped me through this process. More often than not, when I asked if something could be done, his answer was, “Yes!” I cannot amply stress the importance of having a tech-champion on your team. This person is as important as a plumber or an electrician. (Please note, a tech person COULD be an electrician, but an electrician is not necessarily a technology expert! Get the right person for the needed job.)

I wanted the system because of my belief that, despite the conflicting realities, automation is probably more beneficial to seniors than the tech-savvy Millennials. My wife selected faucet handles that will work better for arthritic hands, the AIP contractor suggested a drawer microwave because it is more conducive to someone who might be wheelchair bound. Wet baths were included to eliminate the possibly hazardous step and aesthetically sensitive grab bars were included, just in case. Automation systems can be equally helpful for many of the other things that become a struggle as we age.

The back of the house features sixteen large windows that look out on a wooded area (in the middle of an inner-ring urban/suburban neighborhood.) Without automation, opening and closing them daily could be an onerous task. Insuring nightlights are turned on at night has shown to reduce falls in seniors. That is an easy thing for home automation systems. Nighttime security checks can quickly be achieved by a control system. All of these things should make life for us better as we age. All of these things should not be a burden.

I was reminded of the burden of automation after reading a New York Times opinion feature that shared the fact that automation is NOT saving us any time. Workers using AI to “help” are not saving time. Technology-enhanced homes are not allowing active young homeowners added time to lollygag and “chill.” Statistics state they spend roughly the same amount of time doing (loosely defined) housework as their parents. But why? The creators of these products promised me peeled grapes and a pink pony!

Each time my wife attempts to book a doctor’s appointment online, I am reminded why technology does not always save time. The two-step authentication becoming more and more ubiquitous was probably invented by lawyers in an effort to protect their litigious-prone industry. How many times has a slow server, or a weak Wi-Fi connection caused you to “time-out” of your ability to enter the six-digit code? My moderate dyslexia invariably forces me to reenter the number more than once. Does the cybercrime version of Boris & Natasha really care my annual physical is scheduled for next Thursday?

I’ve never figured automation to save me time. In pre-computer days, when I managed an Engineering Department, I had an assistant. If I needed communication to be sent to people in the company, outside the company, whomever, I asked her to write a note to them about whatever topic was required. Later that day, she had typed a letter covering the required topic. As fax machines came online, I was required to write letters with sketches and details she could not complete. When each of us was given a computer and an email address, all of the correspondence was now my responsibility. My assistant could no longer handle that portion of my workload. I was now the typist. Luckily for her, she was an immensely talented person and went on to manage her own collection of people in a different area of the company. Automation simply meant I now had more work. Different work, but more than I had prior.

I did not buy and have installed a Control 4 home automation system to save time and money. I did not expect to save energy. I did hope a home support network would allow my wife and me to live in our last home longer by eliminating some of the more cumbersome tasks from our daily routine. I still believe this to be true. I am also realistic (and old) enough to know that sometimes you get wasabi and sometimes you get horseradish with food coloring and cornstarch, more often, the latter.

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Technical Lighting Help

Why is Color Fidelity Better Than Color Rendering?

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In my last blog post, I explained the recent recommendation by the CIE (International Commission on Illumination) to move away from CRI and replace it with Rf, CIE General Color Fidelity Index. Almost immediately, I was asked why. It’s a good question. On the surface, they appear to be very similar.

  • Both use a zero to 100 ranking system
  • Both use the same Spectral Power Distribution (SPD)
  • Both compare a source against reference colors

This last point is what makes the biggest difference.

Color Rendering Index (CRI) uses only eight reference colors. All eight are pastels with similar levels of saturation. For years, known flaws included the lack of red, bold colors and flesh tones, but because incandescent light does a good job rendering pastels, it never raised much concern. The rise of LED laid bare the failures.

To solve this key flaw, Rf uses 99 reference colors, evenly spread across the color spectrum. These are also colors drawn from real-world objects and dyes. A wider sampling will deliver a more realistic metric.

One additional pushback I have heard concerns the similar results garnered by each test method. Perhaps the CRI is 90 and Rf is 92. Of course, that is possible. MicroSoft Windows 1.0 could allow us to write a letter and the same can be said about today’s most current operating system. The difference is in all of the other features. As we begin to use and understand Rf, the added features will grow in value. With the added data provided by Rf, one might find one light source does a great job rendering wood tones and another a better with bold blue colors. As lighting professionals, we can select the light that best suits the application. As the CIE address the other know flaws, new measurements will build on this foundation to be more robust method of color measurement.

I can’t stress this more. Find a way to introduce yourself to this new metric. Like commercial lighting professionals have realized before us, the advantages will far outweigh the learning curve.

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Goodbye CRI, Hello?

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You may have heard that the CIE (International Commission on Illumination) has finally agreed with numerous illumination and color of light experts to abandon the Color Rendering Index (CRI) method of measuring the quality of white light. That was the easy part (not really, it took a long time, but stick with me.)

While those of us who simply want to specify and use good light have referred to this characterization as CRI, the CIE calls it Ra, CIE General Color Rendering Index. They are recommending a replacement with Rf, CIE General Color Fidelity Index.

When we lived in an incandescent and fluorescent world, CRI worked fine. As we started to employ more fluorescent and then a total LED replacement, the known flaws in the CRI system became more and more apparent. Something different was needed. Early on, the CIE admitted that CRI was not acceptable, but was noncommittal on a replacement. This world organization is known for its detailed deliberation. When it makes a decision, it comes with a lot of weight.

Over the years, a number of replacement concepts were proposed and rejected until the lighting community was presented with TM-30. While there were a few objections, most everyone agreed this was a superior metric. Much of the commercial lighting industry has already begun using TM-30. We decorative lighting folks have maintained an allegiance to CRI for very clear reasons. It was easy. 100 = good; zero = bad. If we’re close to 100, we should be satisfied. Besides, we have just begun to take light quality seriously, some slack was needed to be given to those of use less technically inclined.

One reason TM-30 is so fully supported is because it is actually two different measurements packed into one metric. There is a one-for-one replacement for CRI or Ra. That is Rf (fidelity.) It also measures color saturation and that portion is call Rg (gamut.) The CIE also recognizes that a single fidelity measurement does not tell the whole story. They are setting a foundation for a more comprehensive metric that could be TM-30, or could be something else.

What Can Decorative Lighting Expect?

I understand change is hard. I was around when decorative manufacturers, retailers and the design community needed to digest a new set of data points. Color Temperature and CRI were rarely discussed and poorly understood prior. Nonetheless, we all rose to the occasion. Here’s what we should expect to see in the coming months and years.

TimingMetric 
The past and currentlyCRIWe may see many decorative manufacturers cling to the old measurement
Coming SoonCRI + RfTo help in the transition, showing both numbers will help users understand the number and the benefits of change
FutureRfWith the term an integral part of the dialog, CRI can then be eliminated
The Desired FutureRf + Rg (?) / TM-30 / ?Everyone understands we need a more comprehensive metric. Will TM-30 be the answer, or a stepping stone to something else?

I don’t know how long it will take for the decorative lighting world to see this change, but I do know, TM-30 was adopted a lot faster than I had expected in the commercial space. For that reason, I urge you to take a minute or two and understand what could be coming your way. Remember when you were the only one who understood CRI? That time is coming again.

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Technical Lighting Help

Data Driven Lighting Selection

A friend of mine is doing a substantial amount of research of interurban transportation of the early 1900s. To aid in his efforts, he has acquired many years of the trade publication, Electric Railway Journal. In the midst of culling this vast haystack of data to find the “needle” he needs, he stumbled across an article covering the testing that was done by General Electric Company’s National Lamp Quality Division for the illumination of railcars. To insure there was adequate lighting at the fare box, aisles and for general passenger comfort, they took readings at multiple locations in the car. To satisfy the manufacturer, they recorded various voltage draws and power consumption. Being mindful of costs, they also compared operating expenses for three lamp options. Basically, this was an extremely thorough examination of the available lamping of the time.

As I read this report, I realized that presenting the information in a trade publication was a very fortunate thing. When selecting a product now, we can always Google, “Top 10 Best [fill-in the blank]” and read a handful of lists and reviews before buying. That would not have been the case in the 1910s. There was probably a low likelihood that a local train car lighting expert was in your neighborhood. Finding expertise was a bigger challenge then, hence the need for trade publications.

Today, there are a lot of lighting options. Almost too many. The introduction of LED has opened the floodgates of choice and we could easily drown from it. I have heard some people toss up their hands and almost give up. “Forget it, just install some pancake recessed!” Ain’t nobody wants to hear that!

What parameters should we use to select lighting? Here’s four key topics that might help make the choice easier. Style, size, lumen output and placement.

Style

Decorative lighting is an integral part of our home’s interior. When using a decorative luminaire, style becomes a very important part of the puzzle. Choose a design that melds with the room, the space and the context. Luminaires are often hanging right in the middle of a living space. They are a dominant aesthetic element. Selecting a style that does not work with the furniture, floor coverings, window dressings and wall decorations will be a huge mistake.

Size

Decorative luminaires should be sized commensurate with the application. I’ve written a few blog posts on this point in the past so I won’t repeat myself, but size relative to place is key. Too small makes the light insignificant, too large allows it to dominate a room. Care should be taken when choosing the size of a luminaire.

Lumen Output

Again, I have included the charts for expected lumen demand in various places multiple times in prior posts, for good reason. You need a specific quantity of light in specific use applications. Follow the recommendations and you will enjoy successful lighting.

Placement

Will you put a light over the mirror in a bathroom and blind the user, or will you use the more visually comforting lights flanking the mirror? Will you use surface mounted pancake LED faux recessed, or the correctly deigned recessed luminaires? Will you diffuse lamping, or will you use bare bulbs? Placing lighting in a location that will serve the room and the user will be the most well received addition to a home.

Sure, the needs of 1910s interurban rail riders seems like it has no bearing on our life a century ahead, but these early users were taking care to employ the right light for the task with the technology available at the time. 100+ years in the further, we should be doing the same.

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Light and Health and Infrared Light

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My last blog was on ultraviolet light, now one on infrared. Do we detect an “unseen” pattern here?

Here’s an interesting twist that few people saw coming. The Journal of Environmental Psychology recently published a report, “Effects of near-infrared radiation in ambient lighting on cognitive performance, emotion and heat rate variability.” While this is an early study and the paper itself states that additional research is needed, this initial review indicates that light minus the near infrared radiation (NIR) found in the sun may have some implications on human health.

Upon the introduction of LED, the elimination of IR light was hailed as a benefit. IR can damage tissues and cells on the body and is typically manifest as a sun burn or eye damage, such as cataracts. This study now indicates that the total elimination could cause some additional concerns, especially as humans spend so much more time indoors under artificial light; more so than our predecessors in an agrarian economy.

In a double-blind study, 151 students were monitored, half in light that contained a normal level of NIR (daylight,) compared with the other half subjected to near zero NIR, typical of standard LED lighting. The absence of NIR was found to influence the human’s physiological and psychological levels.

  • Cognitive performances improved in the participants who received light with normal levels of NIR, resulting in better attention, better perception, improved short term memory, increased working memory and better executive function.
  • Mood also improved in the participants who were tested under light with NIR. They showed increased levels of pleasure, more alertness and higher levels of environmental satisfaction.
  • Subjects exposed to the typical levels of NIR showed beneficial effects on resting high-frequency heart rate variability (HF-HRV) and the HF-HRV response to cognitive demand.

Our old incandescent and fluorescent delivered plenty of light in the infrared range. With LED in the midst of a near total domination of both commercial and industrial settings, humans will be experiencing substantially lower levels of NIR than generations prior. This possible impact on humans must be balanced against the benefits as well as the energy savings earned by more efficient LED. Again, remember, this is an EARLY study. The scientific community will be digging into this issue over the next decade. Stay tuned.

Interested in reading the entire study?

https://www.sciencedirect.com/science/article/pii/S0272494424002573

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Round 2 GUV CALiPER Testing

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[It has been brought to my attention that I transposed a point of data in my paragraph concerning Long Term Performance of UV-C LED when this post was initially released 3-3-2025. I incorrectly stated that there was a 76% loss, when in-fact the product maintained 76% of its initial output. I have corrected that paragraph.]

As I read the finding of the second round of CALiPER testing on Germicidal Ultra Violet (GUV) lighting, I homed in on the final section. “Conclusions and Next Steps.” The report is chockfull of data points and detailed findings that are very interesting, but probably don’t help a typical user. I want to share a few that trouble me and should concern users and specifiers as they consider GUV.

Incomplete Product Performance Data

Some of the products had no performance data and only half had some data available via a website. This lack of information really makes it difficult to consider adding GUV to a space. One would think, when dealing with a light source that included a potentially dangerous byproduct, information would be crucial to the purchase to insure proper installation and a commensurate results. Without it, who would consider a purchase and how could a consumer determine if a purchase would be helpful? This means, only the included marketing information becomes the deciding factor. Remember how marketing told us that we should buy Chesterfield cigarettes because more doctors smoked them? We are reentering the 1950s.

Inaccurate Performance Claims

If you recall the CALiPER testing done for the original LED retrofit bulbs, this was a very common issue, No difference here. One of the great things to come from that process was better facts and more reliable packaging information. Hopefully, that will be the end result of the GUV CALiPER process if it moves forward under the new federal government that is decidedly less receptive to research, technology and education.

Potential for Unsafe Products

This round of testing concentrated on wall mounted upper room luminaires. These units are intended to treat air in a portion of the room NOT occupied by humans. That means, humans can safely navigate the room below, because the light will not reach them. CALiPER found that two of the luminaires emitted lighting below horizon (where people inhabit.) These two, plus an additional two were found to exceed UL 8802 safety limits for irradiance. These could be potentially damaging to humans. When dealing with light in the UV range, care must be taken. Failure can have significant repercussions.

Long-term Performance of UV-C LED

One tested product maintained only 76% of its initial output at 500 hours of operation, despite a claim of 8000 hours of operation. The plotted decline was also very consistent. This is a relatively quick deterioration and the typical consumer might be concerned with a 24% decline in performance in so short a time.

My Thoughts

While we lived through COVID, the rise of a lighting solution to combat airborne pathogens seemed like a godsend. As our memory fades, so too has interest in non-medical applications. The one thing we can guarantee is the blossoming of a new disease and a new problem, quickly followed by a reemergence of interest in this type of lighting solution. That we are doing these reviews now means we might be ready when the time comes. In the meantime, buyers should approach with caution these products. They should also push for a more formulaic review of these luminaires. They should seek out and ask for independent test lab reviews. Only then will manufacturers start to abandon their use of marketing promotions and replace them with fact-base statistics. Once we have that data, we will be ready to battle the next dangerous microbe.

Want to read the full report? Follow this link:

Click to access ssl_caliper-guv-rd2-102824.pdf

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Indirect Light

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A few months ago, I received an unsolicited request to write a post on indirect lighting. This sounded like a great idea to me. I immediately dropped a note into my “reminder file” figuring inspiration would quickly burrow itself into my brain and text would come flowing through my fingers into a MS Word document. Alas, that has not occurred.

Indirect light is a remarkable addition to a room. When my wife and I renovated our second home, we added perimeter lighting to a basement rec-room, tucked behind a ceiling mounted valance. Despite the other layers of light I included in the space, it became the first and typically only light we used. It was comfortable, provided no glare and seemed so natural, despite the fact that it was linear fluorescent, in those pre-LED years. In our third home, I included LED linear over-cabinet and toekick lighting in our kitchen remodel. Again, we use them much more that the four other switches in the room. Clearly, we prefer the output provided by the indirect source.

But, what science did I use when I specified it? Surely there was a method to my madness. Actually, I had no method, just a gut response to the need. In the basement installation, I used the available T8 fluorescent product sizes in double-tube, offset models, because I hated the “dark gap” left when non-offset product was used in long linear lines. I had specific lengths, so I used a combination of 48”, 36” and 24” units that would give me a full and even delivery of illumination.

In the kitchen, it was even less “scientific.” I made a decision to install an “All LED” lit room. At the time, it was quite a challenge. My electrician was VERY excited, knowing he could take the experience with him to his next job. I was a Product Manager at the time and my kitchen along with the kitchens of the Engineers involved in the design became “linear lighting guinea pigs.” We learned about output, how color temperature interacted with room settings and how lumen output informed products. (There were limited LED options at the time.) Like Henry Ford’s famous quote, “You can have any color as long as it is black.” I had one option. I made installation videos while I installed the light that I hoped could be used to help others and in the process. I learn of some issues that would inevitably arise, so I was preemptively prepared for Sales Rep questions. What I did not do and could not do was consider the options, because, they simply did not exist.

Since my early interaction with indirect light, I have tried to quantify my preferences. I’ve tried to digest the WIDE assortment of linear lighting now on the market. I’ve also attempted to integrate the needs of more light required for senior eyes and their preference for indirect light. Couple all of that with the variety of room reflectance and ranges quickly become important.

With that in mind, let’s revisit my previous installations. The double T8 installations hidden behind a valance were producing about 1400 lumens per foot. (Florescent T8 lamping produced between 650 and 750 lumens per foot and there were two, side by side in each fixture.) The valances ran the length of the room on both sides. While I no longer have the details, I believe there was about 25’-0” of light, amounting to 35,000 lumens in a 15’-0” x 28’-0” (420 sq. ft.) room. This was enough to illuminate a room comfortably with no-glare. That may seem like a huge amount of light, but we must remember, because it was indirect, a reasonable proportion is lost in absorption and reflectance.

In my second installation, using early LED linear lighting, I know the output was much lower, approximately 50 lumens per foot. With a linear length of 20’-0” in a 9’-0” x 13’-0” room, that delivered 1000 lumens of light. The toekick at 16’-0” of linear length produced 800 lumens. When used together, 1800 lumens of indirect light was easy to like.

My non-exacting use ranged from 50 to 1400 lumens per foot. Looking at the wide variety of products now on the market, we can easily specify eleven different static white options from 112 lumens per foot to 1163 lumens per foot, and that is from just one company! By developing comfort with this “lumens per foot” metric, it is easy to apply the correct amount to each application.

Today, indirect light is typically produced by linear LED. I wrote two companion blog posts on this topic (https://lightingbyjeffrey.com/2024/01/29/how-to-effectively-select-led-tape-part-one/  https://lightingbyjeffrey.com/2024/02/12/how-to-effectively-select-led-tape-part-two/  ) There is lots included there which can be reused here because most of the content referenced indirect illumination. I’ve reprinted this table, because it relates to applications. Use the range to deal with reflectance variations.

ApplicationLumens per Foot Range
Mood lighting / Light Used as a Background100 to 300
Accent lighting / For Added Aesthetics150 to 500
Task Lighting – Close275 to 500
Task Lighting – Far Away (light location)350 to 700
Indirect Lighting375 to 575
Cove Lighting180 to 500
Principle Lighting in a Room400 to 1000
As a Replacement for Linear Fluorescent Lamping500 to 950
Kitchen Under-Cabinet Lighting175 to 550*

Now, let’s understand the relationship between room size and the indirect light’s lumens per foot delivery. If we consider my original rec-room with the old fluorescent, 420 sq. ft. multiplied by the desired 20Fc illuminance level from the chart below, 8400 lumens is needed.

The indirect light in the kitchen is intentionally less functional, so the 117 sq. ft. against a desired illuminance level of 5Fc would require 585 lumens of light.

Area / TaskDesired Illuminance Level in Footcandles (Fc)
Hallway/Passageway5-10
Conversation Area / Entertaining5-20
Dining10-20
Reading (General)20-50
Bathroom / Grooming20-50
Laundry / Ironing20-50
Kitchen (General)20-50
Kitchen (Work Areas)50-100
Reading (difficult) Study / Hobby / Music50-100
Hand Sewing / Detail Hobby100-200

The 35,000 lumens I liked is four times the anticipated need. The 1800 lumens in the kitchen is closer to three times the need. Because indirect light takes a circuitous path from the light source to the user, much is absorbed in the reflecting surfaces.

Think about this, a mirror only reflects back about 92% of the original. If I measure my above cabinet light directly overhead (12”,) I record 20.7 Fc at the ceiling. My toekick lighting measures 130.8 Fc on the floor below (Very close at 4” to the floor.) Standing in the middle of the room with both systems engaged, I have a mere 3.5 Fc of usable illuminance from 3600 lumens. Obviously, a lot of that light is lost in surface absorption and distance.

To achieve usable levels of indirect light, a 3:1 to 4:1 ratio makes sense. If you want to reach the levels of usable light the second chart suggests, you need to use products that create three to four times that number.

There are more complicated calculations that could be employed to insure exacting levels of light. Many commercial projects first construct models to understand the end result of the proposed light. Both are impractical for the residential space and occasional lighting designers. At the risk of suggesting my hunch, rather than proven data is the way to go, I’ll leave you with a 3:1 to 4:1 ratio.

If anyone else has a better suggestion, or an easy calculation, let me know. Next time, I may be less accommodating when someone suggests a blog post topic!

Categories
Technical Lighting Help

“Let’s Just Eliminate the Stove.”

Photo by AS Photography on Pexels.com

At the recently completed American Lighting Association (ALA) conference, the concept of cost overruns was discussed. The lighting pros in attendance were commiserating the unfortunate fact that light, too often is the victim of an expensive refrigerator. When costs need to be cut, lighting becomes the sacrificial lamb.

I suggested we should all counter that response with a different argument.

Client: “We are spending too much money on the new kitchen. We’ll need to eliminate some of the lighting.”

Lighting Professional: “I have a better solution. Let’s remove the stove.”

At this point, the customer will respond and push back. Of course, a kitchen without a stove isn’t much of a kitchen. A kitchen without proper lighting is equally ineffective. If you can’t see the carrots, dragging out a knife could be a lethal, or at least messy problem.

There is a better way that doesn’t mean the elimination of half the light or one La Cornue. Multiple lighting options should be considered so a good lighting design will be the result.

The first design you offer should be the optimal version. You should include the luminaires that will do the best job, perform the best and deliver the finest design possible.

A second option should include alternatives and the reasons they are second should be included in the notes.

  • “Adequate, but not perfect beam angle”
  • “Shorter expected life span – 25,000 hours vs 60,000”
  • “Increased likelihood of glare”
  • “X”

You might want to offer a third, but I wouldn’t unless you like extra work, or that has been agreed upon when discussing the job.

Sometimes, the customer needs to understand why they are selecting what they are selecting. They might choose a Sub-Zero because it has a reputation and a certain amount of élan, but they do not have that connection to lighting. They can acquire a visceral connection to a chandelier, but functional lighting is different. A stove roasts a chicken, a dishwasher cleans the pots, a freezer makes ice cubes, but they might not realize properly designed recessed cans (pots) deliver glare-free light that supports all of the tasks a user achieves in a kitchen.

The accent lighting layer is an easy victim to cost overruns. In order to swing that copper farmhouse sink, the toekick and above cabinet lighting could be sacrificed. The lighting designer should ask, “At what cost?”

“Why install a Poggenpohl kitchen, if you aren’t going to light it properly?” If you can’t see the beautiful finishes, the seamless craftsmanship and the flawless functionality, what is the point?

In a perfect world, kitchens should be offered at multiple price points, each with commensurate lighting. Here are a few lighting options matched with the overarching kitchen concepts.

Entry Level Kitchens

If the client is furnishing their first home, or if they are young and just starting life’s journey they will likely be using stock cabinets, basic appliances, introductory priced granite countertops and simple flooring. The suggested lighting could be:

  • Decorative surface mounted luminaires – flush or semi-flush, depending on the ceiling height. (Surface mounted “discs” are not an option at ANY price point!!)
  • Good output, LED Tape in a plastic channel as under-cabinet lighting. Depending on price, an integrated under-cabinet option might work. LED Tape is typically less expensive (based on lumens per foot) but still confounds some less skilled electricians.

Mid-Level Kitchens

If the customer is moving into a second or “forever” home, they will likely be using semi-custom cabinets, more elevated appliances with better features, quartz countertops and ceramic or wood flooring. The suggested lighting could be:

  • Pendants at the island that have a size equal to the girth of the surface and a height that conforms with the ceiling height. In other words, avoid using tiny 5” spheres in a room with 10’-0” ceilings over a 48” wide island.
  • Well positioned recessed lighting. They may not have optimal beam angles and they might not be as recessed as those found in a perfect design. (Surface mounted “discs” are not an option at ANY price point!! Yes, I wrote this twice for a reason.)
  • 300 to 500 lumens per foot LED Tape in a channel as under-cabinet lighting
  • Above cabinet accent lighting provided by LED Tape delivering between 150-250 lumens per foot.

Luxury Kitchens

This client might have a kitchen designer. They might be using an interior design specialist or architect. They are familiar with what they want and have the funds to achieve that goal. This is not their first home purchase and might not be their last. They will be specifying the aforementioned La Cornue and Sub-Zero appliances in a SieMatic kitchen. High end backsplash and flooring materials will employed. The suggested lighting could be:

  • Pendants at the island should be perfectly sized to the girth of the counter and height of the ceiling. The quantity used should also fit the scale.
  • A separate dining area might need supplemental lighting and a fine decorative chandelier/pendant/semi-flush should be selected.
  • Well positioned recessed lighting with optimal beam angles and lumen output. They should be recessed into the ceiling a minimum of 2 ½”. (Surface mounted “discs” are not an option at ANY price point!! Once more for effect.) There will never be a reason to replace these, so buy the product that is warrantied for 50,000 hours or higher.
  • 300 to 500 lumens per foot LED Tape in a channel as under-cabinet lighting
  • Above cabinet and toekick accent lighting provided by LED Tape delivering between 150-250 lumens per foot.
  • Under countertop lip accent lighting should also be discussed and considered. It can be a wise alternate to inside drawer lighting.
  • Under island accent lighting (again, LED Tape) at about 200-300 lumens per foot will work nicely
  • There is a good chance this kitchen will feature some display cabinets. They will need to be lit to fully appreciate the items. The necessary illumination can vary widely from 150 to 500 lumens per foot depending on the goal.

There are many differences found in all the kitchen designs in America and they diverge in as many ways as the customer does. Despite that range, no one need go without a stove to have good lighting. Good lighting simply needs to be planned in concert with the rest of the kitchen’s functional elements.