By Stan Walercyk, HCLP, CLEP
It is my impression that most people working for the Designlights Consortium (DLC) and those working for member utilities and rebate organizations dealing with the DLC process think that they and the DLC are a good team and are providing beneficial services.
But it is also my impression that many manufacturers, retrofit contractors, ESCOs, lighting designers, end-customers and others are very frustrated with the DLC and some have even given up trying to change the DLC.
I have tried to get the DLC improve three of their requirements for a number of years with no success. So I wrote this article, and maybe you will have better luck.
Even if the DLC makes these three improvements by the time this article is published, a big question is why it took them so long.
For those not aware of the DLC, a number of utilities and other rebate organizations, which did not have the money or man-power to evaluate and approve commercial LED products for rebates, started to pay DLC, which is a project of the Northeast Energy Efficiency Partnerships (NEEP), to evaluate and approve certain commercial LED products.
In many ways the DLC has been helpful, but in at least three ways, many people including me, do not think so. You can make your own decisions.
Minimim Lumen Requirement
Maybe the best, or in another way worst, example is 2×4 LED troffers or panels and troffer kits, which the DLC requires at least 3000 out of fixture lumens.
Without additional dimming, which is expensive, 3000 lumens is overkill for many applications, including typical offices with good task lights, halls, restrooms, closets and even many classrooms. Especially in offices, excess light usually translates to glare, which is not good. Often less light is better than more light.
I have had thousands of 2×4 troffers retrofitted with 1 fluorescent 3100 lumen 32W F32T8 850 lamp, 0.71 or 0.77 ballast factor (BF) ballast, 1-cove white reflector and if an existing parabolic louver, a new high performance lens. End-users have been quite satisfied. With 0.71 BF ballast, this provides about 1650 out of fixture lumens based on 3100 lamp lumens x 0.71 BF x 0.88 fixture efficiency x 0.85 heat factor. Wattage is 24 – 25, and this usually qualifies for rebates.
But DLC requires 3000 minimal lumens, which is almost twice as much as this good fluorescent solution, and again can be too bright and too glary if there is not dimming. Since LED troffers and troffer kits typically provide about 100 lumen per watt (LPW) out of the fixture, the wattage is about 30, which is higher than the fluorescent option. To get 3000 lumens out of an LED troffer or troffer kit, either additional LEDs are required, which increases product cost, or the LEDs are overdriven, which reduces efficiency and maybe also life. 15 – 20W LED troffers or troffer kits would provide about as much light as the fluorescent equivalent, save more energy and cost less than 3000 lumen LED versions. So DLC, requiring 3000 out of fixture lumens, is actually driving people away from LED and toward fluorescent.
What right does the DLC have to mandate lumens? At this time, why can’t lighting professionals and end-customers be able to decide lumens?
The Lighting Design Lab (LDL) in Seattle has its own LED product requirements, including LPW and color rendering index (CRI), which are good, but does not have lumen requirements, which is also good. At least most people in the Pacific Northwest can use LDL, which allows them to have lower product costs and more savings.
Sometimes 5000+ out of fixture lumens are required, so a minimum 3000 lumen requirement will not help for those applications.
Maximum Kelvin Requirement
Other than for hibays, DLC only allows up to 5000K for interior applications, which makes absolutely no sense regarding what can be called spectrally enhanced lighting or high Scotopic/Photopic (S/P) lighting and what can be called Human Centric Lighting, human factors in lighting, biophilia or other terms.
With higher than 5000K, visual acuity can be maintained while reducing wattage or visual acuity can be increased while maintaining wattage. Usually the former is done.
Good neuroscientists and other qualified experts on this subject will state that over 5000K for most of waking hours can be very good for improved circadian rhythms, short and long term alertness, mood, perception, performance – productivity and sleep.
The DLC will not even approve a product with adjustable Kelvin or correlated color temperature (CCT) that goes over 5000K, even if that product can be used below 5000K.
What right does the DLC have limiting Kelvin at 5000? I have asked them numerous times the rationale for that, but have not received a good answer.
The ‘best’ answer that I received from them is an informal one, which was that the DLC is concerned that some people may buy high CCT LED products, not like them, not buy any more LED products and maybe even tell other people that they should not buy LED products. Maybe the DLC is getting too much information from some fru-fru lighting designers, who only like low CCT.
Why can’t lighting professionals and end-customers be able to choose CCT as long as efficiency and CRI are sufficient?
The LDL has no CCT or Kelvin requirements, and that seems to be working out just fine.
Some lighting companies are focusing in the Northwest, because they can use high CCT products and get rebates for them.
Often people can get rebates with 6500K, 8000K and even higher CCT fluorescent systems.
If you want more information on Human Centric Lighting, click here.
Even the best LED product will not be approved by the DLC if the DLC does not a category for it. So there will probably be no rebates for these products.
This may include wallpacks in interior applications, jelly jar fixtures and various greenhouse lighting fixtures.
Does that make any sense to you?
I ask you, what I have asked the DLC. What right and rationale does the DLC have for minimum lumens, maximum CCT and not approving even the best LED product if it does not fall into an existing category?
Do you think it would be better to be able to use the LDL instead of just the DLC?
If you satisfied or not satisfied with the DLC, you could contact them directly and/or the person at you local utility or rebate provider.
If necessary, it is often best to go with products that do not qualify for rebates. That might motivate the utility or rebate provider to do something, because they will not get credit for the energy savings.
I am consulting on a junior college, which looks like it will go with 2700K – 6500K troffer kits, because it considers the benefits are worth more than getting rebates on products, which only go up to 5000K.
If anybody from the DLC or its members thinks that any of my statements are inaccurate or biased, I would be very willing to have a debate.