Dear Sir,
While I will continue to do lighting retrofits, there seems to be little incentive out there for participation in the EVT Lighting Designer program. My lighting design practice, while using the most energy efficient lighting systems, now focuses on saving customers money on lighting product costs over more typical spec methods. Did you know that currently almost all commercial lighting specs in VT are done by the manufacturers reps? "or equal" is used by electrical engineers and architects- with the unintended effect of allowing lower cost, typically lower quality products to be substituted by competing rep agencies. This leads to "a race to the bottom" in lighting quality. Unfortunately, few engineers and architects understand enough about lighting to prevent this. Project owners are the losers, as the contractors and suppliers enjoy sizable markups on inferior products.
I save customers money by eliminating the high markups, and specifying and supplying the right products to meet the client's needs at a fair price. Because the contractor does not see the cost of the lighting fixtures, this also saves on installation cost. Its typical for electricians to use 2x the fixture cost for their installed cost, which for higher quality products can be too much.
The focus of more of my projects now is on ensuring that my clients benefit not only with energy savings, but also with quality lighting designed to ensure health and wellness. Circadian stimulus is a key health component as determined by the Lighting Research Center at RPI and international lighting agencies. Some energy retrofits have reduced light levels to the point that the spaces can have a negative impact on daylong occupants. Others were overlighted, and then rely on dimming to reach proper light levels- sometimes resulting in noticeable flicker from low cost drivers. I have seen a number of retrofits using magnetic LED strip that are severely underlit, as well as schools which have been delamped to the point that learning is affected. I'd like to help address these issues, but where does one begin?
If you don't have resources available to assist in these types of projects, I quite understand, as Health and wellness are not part of EVT's goals.
Donna Leban, AIA LC
What is Circadian Lighting? Why is it important?
When we adopt good daylighting practices in a building design, we are incorporating circadian lighting. Circadian lighting, by definition, is ambient light that simulates the color spectrum and intensity of daylight. Of course, we don’t live in a climate where every day is perfectly sunny. We also live on a planet where there are many more hours of available daylight in the summer than in the winter, unless you live in the tropics.
Factoid: Burlington, VT has an average of 58 sunny days (up to 30% cloud cover) and 101 partly sunny days (40-70% cloud cover during the daytime). Over the year, we get 49% of the potential available sunshine.
Suffice it to say that circadian lighting in buildings is more important in some climates and parts of the world than others. Or is it? Very few buildings have critical access to daylight in every occupied space during the day. So, anyone who spends a majority of their time indoors is likely not experiencing anything close to circadian lighting unless it is brightly lighted (more than 50 footcandles) with neutral to cool color light in the late morning hours. Unless you live in a glass house, the amount of natural daylight we experience when indoors is usually not sufficient to provide “circadian stimulus”.
Circadian stimulus. This is a new metric created by researchers at Renssaellaer Polytechnic Institute (RPI). It is a calculated measurement that allows us to describe the amount and color characteristics of light needed for effective circadian light exposure in architectural spaces. It is important to note that effective circadian stimulus can be achieved with either daylight or artificial light, or a combination of the two. While the quantity and color spectrum of the light is important in terms of circadian stimulus, the timing of exposure is critical. Late morning exposure to light is critical to regular resetting of circadian cycles. Late day exposure to bright, cool color light is detrimental to these same cycles. This has to do with the regulation of the body’s own production or suppression of melatonin.
Why is melatonin production and circadian stimulus important for human health? Light is the main stimulus that helps reset the body’s circadian rhythm. If disruption occurs to this 24-hr cycle, we experience detrimental effects to physiological functions, neurobehavioral performance, and sleep. This is why we need to pay more attention to not only the kind of light we are using, but also when we are experiencing it.
An excellent example of daylight and artificial lighting combined for morning circadian stimulus. Lumenpulse image credit.