Killing germs with UV lighting – Lighting by Jeffrey

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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

I recently read that Germicidal UV Lighting (GUV) has not produced the sales manufacturers had expected. The amount of available products has quickly plummeted and there is some thought that with the retreat of COVID, people are no longer worrying about airborne particulates and how to protect their family. With the pushback against common-sense vaccines, even in the face of overwhelming scientific evidence, it might not be surprising. Still, the use of light to help combat germs and viruses remains in play. The method of delivery might shift and change as new ideas arise and research becomes more pointed.

Using UV is nothing new. The sun is often considered the ultimate cure-all and of course, it delivers plenty of light in the UV spectrum. In the 1920s, capitalizing on this understanding, Vi-Rex devices were sold to plenty of vulnerable people based on their promise that the electric shocks of UV would make one, “vital, compelling and magnetic.” I’m hoping that was figuratively magnetic, not literal. SAD lights provide a blast of bright UV-filled light for those who are effected by Seasonal Affective Disorder. This more current application is an equally suspicious solution. Does it really work, or is this the 2020s version of wearing a copper bracelet to cure arthritis?

Essentially, viruses are vulnerable to light in certain areas of the electromagnetic spectrum. By adding that type of light to typical luminaires, we can include an effective germ cleanser. The problem is us. Humans have negative reactions to light in this area of the spectrum. When we stay in the sun too long, our skin becomes sunburnt. This is one, very simple, easy to understand reaction to UV. Science-fiction movies remind us of the many other harmful effects of UV and infrared light. Specific spectrum can be VERY damaging. Some areas are deemed safe, but I still read research papers where the exact specifics of “safe” wavelengths is debated. For that reason, care must be employed when considering this option.

I however remain bullish on GUV. The science is still young, but the results are narrowing toward some very specific results. I expect better scientific direction to arrive soon. Coupled with the constant increase in immune resistant antibiotic bacteria (basically, bacteria and fungi that have developed an ability to defeat the drugs designed to kill them) it appears to me that use is inevitable.

As we enter this New Year to growing reports of increases in childhood hospitalization due to viral infections, added help will be required. If GUV employing better research results can help, we should all be receptive. If the germs can improve their defense against antibiotics, then humans should happily add light to their side of the battlefield. In doing so, we must use them knowingly and with greater and greater understanding of the direction of use provided by carefully derived research.