Author: Craig DiLouie

Lighting the Sentient Building

My contribution to the March issue of ELECTRICAL CONTRACTOR describes cutting-edge research RPI is conducting to explore lighting systems that use artificial intelligence to act autonomously in providing optimal light distribution, light level, and color.

My contribution to the March issue of ELECTRICAL CONTRACTOR describes cutting-edge research RPI is conducting to explore lighting systems that use artificial intelligence to act autonomously in providing optimal light distribution, light level, and color.

From the article:

Imagine entering our hypothetical conference room, only this time it lacks discernible controls and is illuminated by a small number of visible luminaires. The lighting system detects where you are and what tasks you and others are performing and then smoothly adjusts output, spectrum and emission pattern to optimize comfort, productivity and circadian function. For example, a troffer mounted over the table provides a focused, high light level for task work, and then automatically transitions to more diffuse lighting for a meeting.

“Just as the vision of a self-driving car will include an embedded expert driver, we are developing the concept of an embedded lighting designer for autonomous lighting systems,” said Robert Karlicek, professor and director of the Center for Lighting Enabled Systems and Applications (LESA) at RPI. “Our research testbed will explore delivering the ‘right light when and where needed,’ where optimized lighting will require no occupant intervention.”

Karlicek added that the data produced by the sensors would then be leveraged into a wide array of “sentient building” operations.

Check out this interesting research effort here.

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NEMA Luminaire Section UGR Task Force Chair Jeremy Yon Talks Glare Metrics

I recently had the opportunity to interview Jeremy Yon, Industry Relations Leader, GE Current, a Daintree company, and Chair of the NEMA Luminaire Section UGR Task Force, on the topic of application of the Unified Glare Rating (UGR) metric. Transcript follows.

I recently had the opportunity to interview Jeremy Yon, Industry Relations Leader, GE Current, a Daintree company, and Chair of the NEMA Luminaire Section UGR Task Force, on the topic of application of the Unified Glare Rating (UGR) metric. This interview was conducted to inform an article that will be published in the September 2022 issue of ELECTRICAL CONTRACTOR, the official publication of NECA. Transcript follows.

DiLouie: NEMA recently published LS 20001-2021, a whitepaper concerning current use of UGR as a glare metric. What was the rationale behind producing this whitepaper?

Yon: Glare is a timeless and universal concern to everyone who cares about lighting. It is one of the most critical aspects of an occupant’s experience with lighting and one of the most devilishly difficult topics. Historically, glare comes in and out of fashion. Because LED efficacy is now slowly increasing, glare is returning to the forefront of the industry’s attention. This topic has been grappled with by true lighting visionaries in the past, and now my NEMA colleagues and I are attempting to re-structure how glare is thought of and talked about so that there can be a common understanding and vocabulary when working together with all stakeholders.

DiLouie: What does UGR, overall and in general, reliably deliver, and what are its limitations?

Yon: The broad aim of UGR is to provide a better way to evaluate glare in indoor settings. However, it is not a simple matter because UGR depends strongly on the specific application; not only in regards to the luminaires, but also in their layout, the shape of the room and the reflectances of the surfaces in the room all affect the value of UGR. Additionally, the location of people in the room and the tasks conducted within the room can affect the experience of glare as well, so different values of UGR may be desired in different applications.

Therefore, we believe much of the confusion and misunderstanding when it comes to UGR is due in part to the three different ways that the term is used – they each have their own purposes and limitations. Since they were unnamed previously, we’ve taken the liberty to recommend that they be called Application UGR (UGRAppl), Luminiare UGR (UGRLum), and Point UGR (UGRPoint).

We’ve come to understand through our research that Application UGR and Point UGR can be tools for lighting designers to get predict what will likely be the visual comfort level for specific locations within an application. These are not absolute determinations and must be balanced with other predictive factors. Application UGR was designed while, and works best when, considering a windowless rectangular room with regularly spaced luminaires (think troffers). Point UGR is possible with computer simulations, but it should not be evaluated by looking at each point as it requires averaging over an area by the user to achieve the intended indication of comfort.

Luminaire UGR is the most common use of the term today and is the most problematic use of the equations. The UGR methodology was not intended to be an absolute measurement. The Luminaire UGR approach does this by forcing an evaluation of a single luminaire type in a specific evaluation space without taking into consideration the space itself (geometry, room finishes, luminaire placement, windows, partitions, multiple luminaire types, etc.). It cannot appropriately predict the likelihood of glare in any space other than that single specifically required condition. NEMA advises strongly against using Luminaire UGR.

DiLouie: What are the most common misconceptions practitioners have about glare and UGR, and what is the reality they should understand?

Yon: I think the most common misconception is to assume that a luminaire can have a UGR rating, ignoring the role of the application. If you look at a table of values produced by the tabular method for a single luminaire, you will see that, depending on the light distribution of the luminaire, the UGR can vary greatly. It clearly does not depend only on the luminaire. Below is an example in which UGR varies from 2.6 to 21.8.

While some may claim that UGR is the best of the various limited glare evaluation tools, that doesn’t mean UGR can deliver more than it is capable. Unless properly evaluated for the specific application in which a luminaire will be used, it can’t give absolute assurance that the luminaire selected is going to meet the required lighting design criteria. To this point, some manufacturers refuse to put Luminaire UGR numbers on their cutsheets. They don’t want to contribute to a misuse of the UGR metric, nor have their customer be the victim of poor lighting design quality because of a misapplied UGR number.

DiLouie: DLC, LEED, and WELL specify a maximum UGR based on glare emitted by the luminaire (UGR-Lum). This offers an advantage of reducing glare to a simple number published on a catalog sheet. NEMA says there are significant disadvantages. What are they?

Yon: All of those rating programs use the Luminaire UGR simplification to get the single value you mention. This creates a situation where a designer thinks they are selecting a product that has the “right number,” but in actuality, they may be selecting one that has more glare than is desired in application. From the example given earlier, the tabular reporting of that luminaire had a range of values from 2.6 to 21.8 – just based on room size and no other factors. With a variation this wide, it simply makes no sense to try and represent a luminaire with a single number.

Because of the selection of only a single reported value, there are many factors that impact the visual experience found in the final application that are not incorporated into Luminaire UGR. Some examples include the room finish (a dark ceiling will be much different than a light ceiling), the luminaire mounting height (high-bay vs office), and non-uniform placement (troffer grids vs artistic slots).

At the same time, luminaires that are designed to achieve only a Luminaire UGR value, and not to minimize glare from an application approach, can have various consequences. The luminous surfaces of the luminaires may be less uniform with easier-to-see LEDs, there may be additional accessories that need to be installed and there may be a feeling that the final spaces are darker, even though there may be adequate horizontal light (some may remember the deep-parabolic troffer days of the 1980s).

DiLouie: NEMA believes UGR-Appl, adopted by ISO and EN 12464-1, is a more appropriate metric to use to predict glare in a space…

Yon: NEMA is saying that UGR should be used in the way intended by the original CIE documents. Simplifying it to a luminaire based value is not correct.

DiLouie: Some organizations utilize UGR-Point, which predicts glare at a point in the space. This similarly places the metric in the space, not at the luminaire, but NEMA cautions about its use. Why?

Yon: Simulations will produce an array of point UGR values in a space. The original UGR uses a “trick” to calculate the average UGR over a 1H x 1H square centered along the walls. If only point calculations are done, as simulation software typically does, then the averaging step is omitted. Judicious positioning of the luminaires and/or the point for calculation can result in large variations in the UGR. “Cherry picking” from a set of UGR point values can yield a misleading value for UGR.

In examples given in the NEMA paper, UGR tables include a variation expectation that is often overlooked. These show expected point-to-point variation values, depending on the spacing of the luminaires. In the example we provided, the variation ranges from a minimum of +3/-3 units to +7.5/3.8 units, making a comparisson against a threshold impossible.

The user of a piece of software should perform proper averaging, either as detailed in the UGR standard (in a 1H x 1H region at the center of two adjacent walls) or in certain situations where occupants are only in specific areas, such as custom areas that best represent their design objectives. Secondly, there are some ambiguities in the UGR standard around handling different sizes of luminaires that can lead to differences between software simulations.

Finally, and most importantly, the designer needs to balance the results with all the other aspects of a lighting design – vertical illumination, presence/design of windows, space use flexibility, circadian exposure objectives, etc.

DiLouie: If UGR-Appl is most advantageous in predicting glare, a challenge is that the procedure appears to be complex and not well understood. What is the solution for this?

Yon: It is complex and not well understood! The fundamental CIE UGR standard (117) has been around since 1995. But oversimplifying it will lead to artificial selection of some luminaires as “good” and others as “bad,” when in fact the goodness/badness is impossible to evaluate outside of the context of the application. With the absence of a simple answer, it is good for all of us to remember that lighting, by definition, is a blending of art and science. This balance is what makes it so interesting and engaging for most of us.

The first recommendation is that luminaires should be used in the manner in which they were intended; if a high bay luminaire is used in an office, there is probably going to be a difference in visual comfort than if a luminaire designed specifically for an office is used. Building on this notion, manufacturers play an important role in determining what appropriate use is. The literature should be clear, and specifiers should ask for details they feel will help complete the project. A qualified lighting professional should be used to bring together all the complexities of lighting into an optimized solution.

Finally, and most importantly, all stakeholders need to come together with researchers to provide consistent and actionable recommendations. The IES is tackling this for some product categories and there is hope for continued engagement. Internationally, there is still work to be done by the CIE.

DiLouie: How should electrical contractors evaluating lighting systems approach it in regards to ensuring a product will not produce objectionable glare? Are there rules of thumb for evaluating application glare?

Yon: The most important rule of thumb is that glare, at its essence, is related to the difference between a bright object and a dark background. This is easy to see in daily life – high-beam headlights that can be disabling at night are barely visible during the day. The first step is to factor in the surfaces around the luminaire – are they light or dark finished? Is there light from other sources hitting the surface to keep it from being dark? The luminaire should fit into those needs by providing diffuse light in circumstances where an overall lighter environment is warranted, controlled and shielded when a dark atmosphere is expected.

It always helpful to think of the extremes – a soft white uniformly backlit luminous ceiling and white walls (if not overly bright) can have almost no glare (to the point that it can be disorienting); whereas a black-box theater goes to extremes to hide the source of the light so as to not draw attention away from the performance. Similarly, luminaires for offices would most likely be expected to have a uniform appearance and contribute to lighting the walls and surfaces, while task-specific lights (such as a wall-wash or a high-bay warehouse aisle light) rely on precision optics that need to be coordinated with the overall viewing expectations of occupants.

DiLouie: What other solutions does NEMA recommend as a way to ensure lighting systems are designed and delivered that minimize glare while serving the best needs of the application?

Yon: The first is to recognize how UGR can be both properly and improperly utilized as a guidance method for good lighting design. We’re hopeful that through the NEMA whitepaper, it is understood that only Application UGR provides suitable guidance in terms of what an occupant will experience in a specific space. In addition, if simulations are done, the individual point UGR values should not be utilized (averaging should be done) and there are assumptions about large and small luminaires that may lead to variations of answers in different software platforms.

Certainly, there is more study and work to be done to improve how we predict glare. It is hopeful that further focus and effort can be made that will simplify how this is done. Yet for now, Application-UGR remains our best option. What we don’t want is a misunderstood lighting metric, such as Luminaire-UGR, being used in good faith efforts to simplify the situation, as this will result in poor outcomes in lighting performance.

DiLouie: If you could tell the entire electrical industry only one thing about UGR, what would it be?

Yon: Our message to the industry is that UGR is an imperfect predicter of glare, but Application UGR is the best method we have today. With the right understanding, it can be an asset to lighting design application. If UGR’s limitations are not understood, such as using Luminaire UGR as a singular number inaccurately across a variety of applications, it undermines the purpose of the metric and can result in poor lighting.

DiLouie: Is there anything else that you’d like to add about this topic?

Yon: NEMA members place a high value on the visual environments our luminaires create. We work together with designers, installers and users to balance the needs of an application to create the most appropriate experience. Balanced factors like efficacy, color rendering, color temperature, uniformity, light distribution, color consistency, etc. all can have different impacts on the perceived glare for each specific application that cannot be factored into a single-value luminaire value.

NEMA welcomes the opportunity to work with all the stakeholders in evolving means to both predict and communicate expectations for visual comfort. Today, Application UGR and averaged Point UGR calculations can be an effective part of an overall lighting design, but they are very limited and should not be applied as a luminaire selection tool.

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Signify’s Rahul Shira Talks Luminaire-Level Lighting Controls

I recently had the opportunity to interview Rahul Shira, Senior Product Marketing Manager, Signify, on the topic of luminaire-level lighting controls (LLLC). Transcript follows.

I recently had the opportunity to interview Rahul Shira, Senior Product Marketing Manager, Signify, on the topic of luminaire-level lighting controls (LLLC). This interview was conducted to inform an article that will be published in the May 2022 issue of tED Magazine, the official publication of the NAED. Transcript follows.

DiLouie: How would you define luminaire-level lighting controls (LLLC)?

Shira: Signify’s definition of luminaire-level lighting controls (LLLC) is derived from the intent of the original definition drafted by the Northwest Energy Efficiency Alliance (NEEA) and endorsed by the DLC. At Signify, we define LLLC as a connected system, where the majority of the luminaires in a deployment are regulated by built-in intelligence. This could be a luminaire-integrated sensor with spatial or environmental sensing capabilities, or it could be a luminaire or lamp with built-in connectivity mechanisms, such as a wireless transmitter and receiver, but no sensing capabilities. The connectivity mechanisms enable users to realize a bidirectional communication link with the lights to support their business needs, such as energy consumption analysis, device diagnostics, or central or manual light level overrides.

DiLouie: How would you characterize demand for LLLC compared to discrete (general lighting + added-on control system), and would you consider this category a trend?

Shira: Overall, demand for lighting controls has increased. In some geographies, LLLC-based systems is even of greater interest than discreet control systems. This trend can be attributed to three factors: 1) wireless connectivity and technology advancements, making it the first-choice option for most retrofit projects. 2) Higher rebates offered by utilities for LLLCs due to the energy savings they offer. 3) Ongoing updates to regulations through various building codes and targeted to minimize energy waste.

DiLouie: What are the benefits of LLLC for electrical distributors, contractors, and owners?


1. Electrical Distributors: LLLCs provide an integrated option between the luminaire and controls, thus reducing the overall Stock Keeping Units (SKU) a distributor may need to onboard and simplifying the management of the flow of goods. In simple terms, by integrating an occupancy and daylight sensor into the luminaire, the SKU counts drop from 3 to 1, a 66.66% drop, and when considered at scale with different luminaire configurations, it translates into significant savings for the distributors. The second soft benefit for distributors is the learning curve their internal staff may need for discrete controls in contrast to an LLLC offering, which can easily fit into their existing processes.

2. Contractors and ESCOs (Installers): The time and money required to cut holes in the ceiling for mounting discrete sensors; the planning required to install discrete controls panels in the electrical room or a distributed controller in the plenum; and the additional materials costs associated with copper, piping and accessories to connect the dimming wires to luminaires can quickly add up and can offshoot the allocated budgets. LLLCs eliminate this nondifferentiated work for the installers and keeps the primary effort limited to luminaire installation. Signify’s Interact Pro scalable system is a wireless LLLC system that can save up to 80% on installation costs when compared with conventional discrete controls. Moreover, because Interact Pro is a cloud-based connected system, installers can proactively offer maintenance services to their clients, giving them an additional revenue stream to grow their business. Finally, LLLCs tend to be more intuitive to configure and commission, making it easier for installers to execute tasks and customize settings as a response to a last-minute change request from the end user, thus helping them build their brand value and trust.

3. Owners – According to research published by the DLC, where they analyzed 194 installs, the energy savings from LLLCs were, on average, 28% higher than that from non-LLLCs. Solutions like the Interact Pro scalable system can push the energy savings bar further with its unique adaptive dimming and dwell time features, which provide the right light levels at the right moment and the right location.

LLLCs with wireless communication technology also offer the flexibility for owners to re-configure lighting control areas, without any disruptions to existing electrical wiring schemes, to easily align with their desk layouts, which, as we know, is changing frequently these days to adhere to physical distancing measures, for example.

With connected LLLCs, owners can gain granular insights on energy use, occupancy patterns, environmental monitoring and space usage, to optimize their operational expenses further.

DiLouie: What are the advantages of LLLC that are driving adoption? What are ideal applications for LLLC?

Shira: Adoption has been growing due to the:

• Documented energy savings benefits by industry partners such as DLC
• Popularity of wireless controls for retrofit markets because of an aggressive ROI model, lower installation costs and flexibility of re-configuration throughout the life cycle of the installation.
• Need to comply with latest regulations and building codes
• Planning for the future – LLLCs like Interact Pro can be deployed in a standalone manner, i.e. without installing any gateways or backend infrastructure, but then can be scaled up to a connected offering by adding back-end building blocks like a gateway or cloud access, whenever deemed fit. This is like a Lego model, where customers can keep accessing new features and benefits by building on top of the foundation that was laid on day 1.

These unique characteristics of LLLCs makes them ideal for schools, universities, libraries, offices, warehouses, parking garages and healthcare facilities.

DiLouie: Looking specifically at retrofit projects, how do the simplicity and economics of installation for an onboard control solution impact the project economics and likelihood of controls being added to the project?

Shira: In retrofit projects, LLLCs unlock the path to claim higher rebates. In most geographies, these rebates range from $15 to $65 per sensor integrated into an LED luminaire and are in addition to the rebates offered for installing LED lights. When coupled with the installation savings and deep energy savings (+28% over DLC average for non-LLLCs) offered by LLLCs, an ROI of less than 2 years or even 1 year becomes very achievable.

LEDs have a longer life span, but controls capabilities are expected to evolve at a faster rate with new innovations. Installing LLLCs means that end users’ retrofit strategy is future-oriented and can easily adapt to evolving business needs.

DiLouie: What are the disadvantages of LLLC? In what applications or application conditions would such a solution be less desirable?

Shira: LLLCs add cost over a base luminaire due to the additional value offered by integrated controls with respect to energy savings. But in some applications like heavy duty manufacturing facilities, where life safety and security supersedes energy savings or where lights need to operate on a schedule such as in a retail store, LLLCs may not be a good fit, unless there is a need for collecting spatial data from the lighting infrastructure.

DiLouie: For what luminaire types are LLLC options available? For what luminaire type or types is LLLC most popular or otherwise advantageous?

Shira: LLLCs are popular in common spaces like a classroom, open office or meeting rooms, for example, where energy savings can be maximized with features like adaptive dimming and dwell time, and where there is the need to alter lighting controls zones/areas frequently. These spaces are typically designed with troffers, linear recessed or suspended luminaires and downlights. In retrofit applications, an LLLC with a retrofit kit is popular.

In highbay applications like warehouse settings, LLLCs are often deployed, as occupancy patterns in these applications are uneven and can be brief. End users can use LLLCs to flexibly re-zone the lights as per their warehouse’s modified aisle structure and only ramp up those lights that are directly detecting motion within the aisle while keeping the rest of the lights in the same aisle at a low background level. This type of adaptive behavior delivers significant energy savings without compromising user safety and comfort.

DiLouie: Understanding that there may be many product options, what are basic, common configurations? How do they typically install, configure for sequences of operation, intelligence inside or outside the luminaire, operate independently or group, and how is control operation managed after installation?

Shira: LLLCs, like the Interact Pro scalable system, are specified by selecting the appropriate sensor option code on the luminaire spec sheets and configured on-site by a non-technical or trained installer using an intuitive configuration App. The App guides the installer on critical steps such as creating lighting groups, altering sensor parameters, trimming the maximum light output etc. Installers can also use the App to execute a code-compliant sequence of operations in a secured manner, thus making the overall process straightforward with minimum dependencies.

If the project evolves over time, the installer can update that same install to the next level by adding a gateway and unlocking additional capabilities like energy reporting, asset performance diagnostics, scheduling, remote monitoring, firmware updates, etc. One of the main tenets of Interact Pro is to prioritize localized outcomes; therefore, intelligence is always retained in the local devices; for example, the link between a wall switch and the LLLCs is independent of whether the project involves a wireless gateway for coordinating system data or not. If the gateway goes offline, the intelligent functions like occupancy sensing or dimming are retained.

External devices like gateways act as coordinating hardware to cloud-based applications, so customers always stay up-to-date with the latest innovations.

DiLouie: Do any special design factors need to be learned or addressed? Is there anything different about LLLC that requires special training or changes in traditional design and installation practices?

Shira: LLLCs with wireless technology are designed to be intuitive and self-serviced; therefore, the learning curve for installers is rapid. One consideration installers will need to take on-board is the planning for wireless mesh continuity. Depending upon the space dynamics, they must consider tactics related to wireless node locations and range. One of the benefits of LLLCs is that a sensor is made available on every luminaire, which reduces or even eliminates the planning and cross checks required to identify sensing blind spots on a project.

DiLouie: If you could tell the entire electrical industry just one thing about LLLC, what would it be?

Shira: LLLCs are the future of lighting control systems. They can help end users maximize their sustainability goals, enhance operational efficiencies, lower maintenance costs and drive employee engagement. Systems like Interact Pro can help them stay relevant in line with their evolving business needs.

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BriteSwitch’s Leendert Jan Enthoven Talks 2022 Lighting Rebate Outlook

I recently had the opportunity to interview Leendert Jan Enthoven, President, BriteSwitch, LLC, a rebate fulfillment firm, on the topic of 2022 commercial lighting rebates and rebate trends.

I recently had the opportunity to interview Leendert Jan Enthoven, President, BriteSwitch, LLC, a rebate fulfillment firm, on the topic of 2022 commercial lighting rebates and rebate trends. This interview was conducted to inform articles for the May issue of ELECTRICAL CONTRACTOR and the March feature for the Lighting Controls Association, where average rebate dollars for popular lighting and control rebates will be published. Transcript follows.

DiLouie: How would you characterize the current commercial prescriptive lighting rebate opportunity in the United States? What is the current overall level and trend in funding?

Enthoven: 2022 has proven to be another strong year for commercial lighting rebates. Currently, 77% of the US has a rebate for commercial lighting or controls. That’s up from 74% we saw last year and close to the highest we have on record, 79% in 2017. While most of the country has incentives available, there still are some notable hold-outs like Alaska, Kansas, North Dakota, Ohio, and West Virginia.

DiLouie: How did the pandemic affect rebate availability in 2021, and what impact will this have on 2022? Are things back to “normal”?

Enthoven: The pandemic didn’t affect the availability of rebates in 2021. Most programs continued as expected throughout the year.

As an effect of the pandemic, we noticed that rebate amounts increased throughout 2021. Towards the end of the year, programs either increased their incentives or offered limited-time bonus programs that provided temporary increases of anywhere from 10% to 100%. In Q4 of last year, we saw that roughly 20% of the rebate programs in the US were offering some kind of bonus to try to spur participation.

DiLouie: What are the top 3-5 trends in lighting rebates and what impact are they having on demand for energy-efficient lighting?

Enthoven: Overall, the rebate amounts for LED solutions stayed relatively flat for 2022. That’s a big change from the past. Historically, LED rebate amounts have dropped 10 – 20% each year. Last year was the first year they stayed flat, and this year continues that trend. The price increases seen across the industry, as well as lack of active projects, are probably the reasons behind this change.

2022 has also proven a strong year for rebates for horticulture lighting. The number of rebates for horticulture lighting has tripled over the last year. The rebate amounts for horticulture lighting have always been relatively high, but the new programs have brought the average amount down by roughly 25%. Still, even with that decrease, it’s the product category with one of the highest rebate amounts at an average of $102 per fixture. We also noticed that in 2022, a lot of the horticulture rebates have switched from custom to prescriptive, making them easier to estimate and file for.

We saw that incentive amounts varied a lot throughout the year last year. For most programs, a rebate amount will be set at the beginning of the year and remain consistent. Last year, adjustments were going on through the year. Most of this was to adjust the levels to take advantage of the available program budgets. This means distributors and contractors have to stay on top of the programs and changes that might be occurring.

DiLouie: What are the top 3-5 trends in lighting control rebates and what impact are they having on demand for lighting controls?

Enthoven: Lighting controls rebate amounts continue to remain consistent. Over the past 14 years, we’ve noticed incredible stability in the rebates for this category.

The number of utilities offering rebates for Networked Lighting Controls (NLC) increased by 16% in 2022. In most cases, if there is a lighting rebate available, NLC will also receive an incentive. These rebates are usually on top of, and not replacing, the rebates for standard lighting controls.

DiLouie: What role do electric vehicles and electric-vehicle charging stations play in rebates now? How do they work, and what are opportunities for electrical contractors and distributors in this category?

Enthoven: EV charging equipment, also called EVSE, is a growing opportunity for electrical contractors and distributors. It’s a relatively new segment with tremendous growth potential in the next few years. We’ve seen rebates, incentives, and grants for EV chargers skyrocket over the past year. These rebates significantly reduce the cost of installing EV chargers, but they may present a challenge. Rebates for EV chargers are much different from rebates for energy-efficient products like lighting or HVAC. While they both provide incentives, they’re more like a distant cousin than a sibling. They come from different organizations, run on different timelines, and are often structured differently. It takes a significant amount of time to fully understand them for even a seasoned rebate veteran.

One of the biggest differences between traditional lighting rebates and EVSE rebates is the sources of funding. For lighting, the rebates are typically through the utility. For EV charging stations, it can come from a variety of sources like the utility, state, county, municipality, or others. Sometimes several programs can even overlap, and you have to select which is the best for each individual project. We’ve been tracking energy efficiency rebates for 14 years, and there were so many differences with EV charging rebates that we had to develop a whole new database to capture and identify all the rebates correctly.

That being said, there’s a tremendous opportunity out there as the electrical charging infrastructure grows in North America. The number of rebates for Level 3, or DC fast-changing, EV charging stations increased by over 20% just in the past three months.

DiLouie: How would you characterize growth in lighting control rebates? Where do you see this trend headed in the future?

Enthoven: Over the past 14 years, lighting control rebates have always been remarkably stable, with dollar amounts and rebate availability being relatively consistent between the years. Most rebate programs in North America offer an incentive for control solutions, but they’re often tucked away in the back pages of a rebate catalog and not highly emphasized. It’s a shame, because the average rebate amounts for controls are relatively high compared to the cost, making them a relatively inexpensive upsell to most lighting retrofit projects.

DiLouie: How would you characterize growth in networked lighting control rebates?

Enthoven: The number of utilities incentivizing networked lighting controls increased by 16% in the past year. The rebate amount itself didn’t change much. Most rebate programs seem excited by the opportunity that NLC presents, but the consensus is that the growth of these systems is slower than expected. One of the biggest challenges seems to be educating the marketplace on how to market and sell these solutions effectively.

DiLouie: What are the most popular models for networked lighting control rebates?

Enthoven: Most of the rebates for NLC are on a “per fixture installed” basis. Filing for incentives for NLC can be tricky. Just one project can have a combination of standard control rebates, standard lighting rebates, and NLC rebates.

DiLouie: What do electrical contractors need to know about helping their customers gain rebates?

Enthoven: The two biggest issues that contractors working on rebates run into are pre-approval and product selection.

A majority of rebate programs require pre-approval before installation. The amount of time pre-approval takes varies depending on the rebate program, but the average is 3 – 4 weeks across North America. Contractors must make sure to allow themselves time to get pre-approval before a project is slated to begin. It’s better to start on the paperwork as early as possible to make sure rebates don’t delay the project.

Product selection is also critical when it comes to rebates. Many programs have strict requirements for what type of lighting is installed. The most common requirements are that the LED is EnergyStar or Design Lights Consortium listed, with over 3/4 of programs requiring certification to receive incentives. Contractors must make sure the product they’re using is currently on the DLC or EnergyStar website; a logo on a spec sheet is not sufficient proof. It’s even more important this year, as DLC will transition from version 5.0 to 5.1 later this year.

DiLouie: Where do you see rebates going in the future?

Enthoven: If price increases, material scarcity, and inflation keep on track, I think commercial lighting rebates will remain stable, if not increase, in the future. For lighting upgrades, the early adopters and the low-hanging-fruit opportunities have already made the switch, and now it’s a matter of convincing the hold-outs, which may need more financial incentives to make the switch.

DiLouie: If you could tell all lighting professionals only one thing about lighting and control rebates, what would it be?

Enthoven: If you do not include rebates on all of your quotes, you’re missing out on a huge opportunity. The rebates allow you to lower the perceived price to your customers without impacting your margin. They also show your customers the value and expertise you add. Rebate paperwork can be a cumbersome burden, but don’t let that stop you. Having a dedicated person at your company to handle rebates, or outsourcing to a third-party rebate processor, can reduce the hassle.

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Field-Adjustable Lighting

Field-adjustable (aka field-selectable) lighting is staple LED light fixtures and lamps that allow field selection of preset operating parameters such as light output and correlated color temperature (CCT). For the electrical distributor, they offer a means to consolidate inventory and more flexibly satisfy local demand for lighting products.

Below is my contribution to the March 2022 issue of tED Magazine, the official publication of the NAED. Reprinted with permission.

Field-adjustable (aka field-selectable) lighting is LED light fixtures and lamps that allow field selection of preset operating parameters such as light output and correlated color temperature (CCT). For the electrical distributor, they offer a means to consolidate inventory and more flexibly satisfy local demand for lighting products.

On the luminaire side, adjustability started with lower-wattage products such as downlights, troffers, and panels and has since moved into other categories including high-bays and undercabinet luminaires. While predominant for indoor lighting, the adjustability trend has begun to enter outdoor categories such as floodlights, wall packs, and area lighting.

“Field adjustability is an emerging trend across most categories,” said Ross Barna, Chief Executive Officer of RAB Lighting, Inc. “While still not in the majority of lighting products sold today, I would not be surprised to see field-adjustable features in the majority of products within the next couple years.”

“The demand for field-adjustable luminaires continues to grow as distributors are maximizing limited warehouse space,” said Eric Jerger, VP, and GM, Indoor Lighting, Cooper Lighting Solutions. “Field-selectable luminaires offer multiple products in one, saving distributors money by stocking less inventory while still being able to meet the needs of their customers.”

How it works

The lighting product is functionally the same as a static-output luminaire or lamp but with a mechanism allowing adjustability of the light emission. For indoor lighting, this predominantly entailed ability to select light output, which has since evolved to include CCT. For outdoor and high-bay indoor lighting, it predominantly involves adjustability of light output. Other adjustability may be available, such as light distribution (e.g., a troffer with a choice of three reflectors) and ability to turn an outdoor photocell On/Off.

The most common adjustment mechanism is a set of mechanical switches or knobs integral to the driver or wired to it, which offer various output levels based on several labeled factory-preset steps. These manual controls cause the driver to draw more or less current based on the desired light output and manage the power between warm/cool LED arrays to tune color output. In the case of luminaires, they are typically set once and then installed. Some smart products can be controlled wirelessly using an app on a smartphone or using a lighting control system, allowing relatively easy, low-labor adjustment at any time to accommodate changing user needs.

Image courtesy of Cooper Lighting Solutions.

“Field-selectable products can be used anywhere,” Jerger said. “Whether it’s a residential homeowner or a schoolteacher in an education environment or a facility manager in a warehouse, field-selectable products are simple for contractors to install while providing long-lasting benefits.”

Distributor benefits

“For the electrical distributor, the main benefits are flexibility and availability,” said Andrew Banovic, Product Director Commercial Indoor Lighting, Acuity Brands Lighting. “Two of the largest investments in the distribution business are inventory and space to store it. Field-adjustable luminaires allow for drastic working-capital reductions, as well as increasing the turns on the SKUs that are being stocked. This also can eliminate a great deal of returns as a good percentage of returns to a distributor are because of lumen output or color changes that are needed.”

While the supply chain math is complex, Banovic offered a simplified evaluation. Acuity has found a combination of light output and CCT adjustment to be most popular, which allows a single adjustable-output luminaire to replace up to nine static-output models that cover most of the configurations needed for a given luminaire type. If three models can be serviced by a single model, a distributor can cut inventory in half without reducing service levels. If replacing nine models, it goes even lower. Banovic compared it to multi- and universal-voltage drivers and ballasts, which caught on quickly and became the new standard.

He offered an example demonstrating the utility of field adjustability. A local distributor stocks 200 static-output luminaires offering a mix of lumen and CCT packages. A customer orders 60 of the luminaire type, not caring about light output or CCT, as long as they match. Unfortunately, the distributor keeps half the units at 3500K and the other half at 4000K, and half at a high and half at a low light output. As a result, the distributor can’t fulfill the order on the spot. If the luminaires were field-adjustable, it could.

Another example is applicable to retrofits. If field-adjustable luminaires are available, a building with multiple space types and ceiling heights would not need a highly precise audit and specification of lumen packages. The contractor would order a large lot of adjustable lay-in luminaires instead of specific lumen packages in precise quantities that may not be in stock.

“Distributors these days are facing a very challenging environment, where supply chains are unreliable and inflationary pressure is pushing costs up across the economy,” Barna pointed out. “Being able to invest in inventory that can hit many birds with one stone is simply the best option to win in today’s market.”

With the added engineering and value, these luminaires may present a cost premium. While their core utility is fairly broad, they may not make as much sense for highly specified projects with comfortable lead times.

One question that will need to be answered in retrofit situations is whether and in what way the product qualifies for utility rebates. The DesignLights Consortium (DLC) allows field-adjustable luminaires in its Qualified Products List, which many rebate programs use to qualify LED products. BriteSwitch, a rebate fulfillment company, said it has not seen any rebate program expressly exclude field-adjustable luminaires. They added, however, that rebate programs vary in how they treat the luminaires, with recognizing only the DLC-listed wattage (maximum wattage), and others recognizing a lower wattage with some means of verification. As a result, it may be beneficial for distributors to confirm how their local programs handle it, select DLC-listed luminaires if required, and, if they’re managing the rebate, to prefile for approval. In 2021, BriteSwitch reported the average rebate for a field-adjustable troffer/panel, downlight, or retrofit kit was $33-34; $120 for a high-bay luminaire; and $91-97 for outdoor wall and pole/arm mount luminaires.

Final word

“Try them,” Banovic advised. “If you haven’t stocked any yet, add a pallet to your warehouse. See how fast it flies off the shelf and how fast you can get on and off job sites. You will never go back.”

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DLC’s Levin Nock on the New LUNA Technical Requirements for Outdoor Lighting

I recently had the opportunity to interview Levin Nock, PhD, Senior Technical Manager, DesignLights Consortium (DLC), for an article about the DLC’s new LUNA requirements I’m writing for the June issue of ELECTRICAL CONTRACTOR. Transcript follows.

I recently had the opportunity to interview Levin Nock, PhD, Senior Technical Manager, DesignLights Consortium (DLC), for an article about the DLC’s new LUNA requirements I’m writing for the June issue of ELECTRICAL CONTRACTOR. Transcript follows.

DiLouie: How prominent are outdoor luminaires in utility rebate programs, and what role does the DLC and the Qualified Products List play in these programs?

Nock: Outdoor luminaires comprise nearly half of all the products on the DLC Solid State Lighting Qualified Products List. According to BriteSwitch energy information, 90% of energy efficiency programs across most of the US and Canada offer rebates for DLC qualified outdoor lighting.

DiLouie: Generally, what is the purpose of LUNA Technical Requirements V1.0?

Nock: The DLC LUNA requirements are intended to mitigate negative impacts of lighting at night by establishing system performance specifications and best practices with the following goals:

1. Minimize lighting energy use. In addition to meeting the efficacy thresholds of the DLC’s SSL V5.1 Technical Requirements, LUNA qualified products must meet additional dimming, control, and shielding requirements to ensure efficient use of lighting energy. These thresholds will help efficiency programs meet or exceed their energy savings goals and end users reduce operational costs.

2. Minimize light pollution. The LUNA program introduces requirements for light distribution, correlated color temperature (CCT), and dimming controls that ensure less light is scattered into the atmosphere, resulting in reduction of light trespass and sky glow, and darker skies for stargazers, astronomers, and wildlife.

3. Provide appropriate visibility for people. The LUNA program incorporates all SSL V5.1 spectral quality requirements, BUG reporting requirements, and additional spectral power distribution and intensity distribution reporting requirements, enabling lighting installations to meet recommended practices and voluntary guidelines for dark-sky best practices.

DiLouie: Is it complementary to current DLC SSL outdoor lighting requirements, or will it be integrated?

Nock: LUNA Technical Requirements V1.0 complement existing DLC requirements for outdoor lighting, with additional requirements that are specific to enabling the responsible application of light at night. LUNA qualified products not only meet the existing DLC SSL V5.1 requirements for lighting quality, but also have attributes that help limit light pollution, sky glow, and light trespass.

DiLouie: What are the benefits of LUNA for owners, contractors, distributors, designers, manufacturers?

Nock: LUNA provides a clear way to address light pollution and light trespass while saving electricity and qualifying for energy efficiency rebates and incentives. The LUNA program qualifies warm white LED luminaires that will help meet dark sky policies and ordinances. These products can be used to meet the prescriptive application guidance in the Joint IDA-IES Model Lighting Ordinance (MLO). LUNA products can also be used to meet the light pollution and trespass requirements for LEED certification. And LUNA products of 2700K to 3000K CCT can be used to meet the light pollution and trespass requirements for 2021 WELL certification.

DiLouie: What does the DLC anticipate for participation by the end of 2022?

Nock: Considering that a third of all artificial outdoor light in the US is lost by unshielded luminaires – costing facility owners over $3 billion every year – and that light pollution consciousness as well as regulations are proliferating, we anticipate extensive participation by the end of 2022. Readers may find the actual count of products that meet LUNA requirements on the DLC QPL as they become qualified in mid-2022.

DiLouie: In recent years, the DLC broadened its interest in energy efficiency by addressing lighting quality issues with indoor lighting. What was the rationale for doing something similar for outdoor lighting?

Nock: The US National Park Service estimates that at the current rate of increasing light pollution, no dark skies will remain in the continental US by 2025. The DLC has played an important role in enabling the rapid conversion of outdoor lighting to energy-saving LED lighting. Due to a variety of factors including lack of proper application knowledge in the market, the unintended consequence of rapidly increasing light pollution has been identified as an issue. The DLC Technical Requirements have been updated to address lighting quality issues found in both indoor and now outdoor lighting, because we recognize the need to prevent more light pollution and the opportunity to resolve the existing issues. Specifically, the LUNA program enables selection of products that will limit light pollution and trespass.

DiLouie: What impact do you see LUNA having on rebate programs, the market, and the state of outdoor lighting? How do you see LUNA fitting into local ordinances and the IES Model Lighting Ordinance?

Nock: In terms of energy efficiency rebate programs, we expect LUNA qualified products to continue to receive rebates because they meet DLC SSL V5.1 requirements for energy efficiency. In terms of the market and the state of outdoor lighting, we hope that light pollution will decrease as LUNA qualified outdoor lighting products are installed following the IDA-IES Five Principles for Responsible Outdoor Lighting, which essentially call for appropriate consideration of lighting needs for outdoor projects.

LUNA qualified products also enable specifiers to meet local ordinances related to light pollution and trespass using warm white light and meet the prescriptive application guidance in the IES Model Lighting Ordinance.

DiLouie: What impact do you see LUNA having on product development? What percentage of the market currently complies, and how and where will manufacturers need to stretch to comply?

Nock: In terms of product development and the shifting market, we expect to see:

1) more decorative roadway/area luminaires with less uplight, based on the LUNA uplight requirement of U2 or lower;
2) more luminaires with CCT of 2200 K to 2700 K at 105 lumens per watt or higher, based on LUNA spectral and efficacy requirements;
3) more public sharing of luminaire spectral data;
4) more listings of shielded products, due to LUNA shielding efficacy allowances;
5) more efforts to standardize outdoor chromaticity specifications for white and amber spectra; and
6) a broader selection of DLC-qualified bollards, due to the LUNA efficacy allowance.

In terms of compliance, most DLC qualified roadway and area luminaires already have an uplight rating of U0 or U1, and many have a family member available at 3000K CCT. The biggest stretch will be for optical limitations in decorative products and for bollards, even with the efficacy allowance for bollards. The biggest opportunity is likely to be newly qualified products at the lowest white light CCTs.

DiLouie: Controllability is required. What was the rationale for including it, and what are the benefits of providing it?

Nock: Controllability is the key to using light where it’s needed and when it’s needed. Controllability is also a key factor for advanced energy savings.

Whenever an outdoor luminaire is dimmed, by whatever means, sky glow is reduced during the dimmed times. This is true even for U0 luminaires because of reflections from the ground and other surfaces. Dimming can also mitigate light trespass and overlighting.

Also, considering that dark sky ordinances are proliferating rapidly throughout the world, installing a controllable product with a standardized control receptacle today reduces the risk of obsolescence tomorrow. While standardized control receptacles are not required in this version, the QPL will make it easier to find these products.

In terms of requirements for controllability, all LUNA qualified products are continuously dimmable to 20% or less of maximum light output. In addition, details about controllability capabilities and communication protocols are publicly available on the DLC QPL, to support easier selection of lighting products and NLC products that are likely to be compatible with one another.

DiLouie: What control scenarios do you see being enacted using the controllability capability required in LUNA?

Nock: To ensure that light is no brighter than necessary, high-end trim enables specifiers to meet design requirements without overlighting. To ensure that light is only used when it is useful, outdoor lighting can be dimmed down as far as appropriate, as frequently as appropriate. For example, when fewer cars and people are present later at night, lower light levels can be scheduled for street and roadway lighting, compared to evening and morning rush hours when more illumination is needed per ANSI/IES RP-8-21. Similarly, occupancy sensors for area lighting can dim the lights whenever an area is unoccupied.

Smart city projects sometimes invest in networked lighting controls (NLC) with various types of sensors plus centralized dashboards for remote diagnostics, scheduling and energy reporting. However, many LED-retrofit projects do not yet include NLC. New LED luminaires are likely to remain in the field for 15 to 20 years, so future upgrades are an important aspect of controllability and sustainability, to avoid premature replacement. A LUNA-qualified luminaire chosen with a standardized control receptacle and a digital D4i driver can be installed cost-effectively today with either a simple standalone photocontroller, or a standalone photocontroller with part-night-dimming and field-adjustable high-end trim. In the future, as value propositions mature, for instance with 5G buildout, each control receptacle can accept a new piece of digital hardware, to support NLC plus additional types of sensors.

DiLouie: What education and training do contractors, distributors, etc. need to properly implement LUNA-compliant solutions?

Nock: Appropriate project design begins with consideration of the IDA-IES Five Principles for Responsible Outdoor Lighting shown below:

Beyond that, design and application guidance is available from the Illuminating Engineering Society (IES). An extensive list of references is available in the LUNA Technical Requirements.

The DLC recommends that, when possible, a qualified lighting professional assist in designing and implementing a complete project that meets all of an owner’s project requirements, including minimizing light pollution.

DiLouie: If you could tell the entire electrical industry just one thing about LUNA, what would it be?

Nock: With all the infrastructure and roadway lighting projects that will happen in the next few years, now is the time to ensure that lighting solutions minimize light pollution and support decarbonization goals. If practitioners and owners do not minimize light pollution and guard against premature replacement as primary design goals, then the opportunity will be lost for decades. With LUNA qualified products, decision makers can be confident of saving energy AND following best environmental practices for nighttime lighting.

DiLouie: Is there anything else you’d like to add about this topic?

Nock: Lighting is no different than other human inventions and activities in that it does not occur within a vacuum. What, where, and how we illuminate our outdoor spaces has impacts – sometimes profound – on neighboring human communities, wildlife, the environment, and the ability to enjoy and study the night sky. LUNA supports a more holistic view of nighttime lighting that provides appropriate illumination for people, while mitigating light pollution and reining in billions of dollars in energy waste that contributes to the climate crisis.

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Lighting Predictions 2030

My contribution to the January 2022 of ELECTRICAL CONTRACTOR looks at BEYOND 2030, a publication by the Illuminating Engineering Society in which industry thought leaders imagine the state of lighting in 2030 and beyond, challenges our industry faces this decade, and where it should focus its energies.

My contribution to the January 2022 of ELECTRICAL CONTRACTOR looks at BEYOND 2030, a publication by the Illuminating Engineering Society in which industry thought leaders imagine the state of lighting in 2030 and beyond, challenges our industry faces this decade, and where it should focus its energies.

Media-driven environments, networked controls, DC power and healthy lighting are just a few topics covered, providing a palette of fascinating possibilities for the future of light. As an example of the predictions:

Mark Lien’s “Lighting Forecast by the Decades” is a snapshot piece packing many predictions. By 2030, he says, LED will have saturated the exterior lighting market. Energy standards will have been consolidated or eliminated, with only a minimum and a stretch standard offered. Government will shift from focusing on boosting energy efficiency to minimizing carbon. Renewable energy will be even more attractive. Augmented reality will enable a preview of how lighting will look and perform in a space.

By 2040, Lien adds, exterior lighting will center around a digital platform for a menu of technologies that includes light. Solar power for exterior lighting will be more efficient, while roadway lighting will adapt to self-driving vehicles. Glare will still be an issue, while lighting designed to optimize health will be widely adopted.

What do you think? Where is lighting headed during this decade?

Click here to check it out.

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National Building Stock Study Reveals Ongoing Lighting Upgrade Opportunity

Commercial buildings in the United States are trending larger and more commonly feature LED lighting and occupancy sensors. While traditional light sources have declined in use, they remain prevalent in the nation’s estimated 5.9 million buildings, spelling a significant continuing upgrade opportunity, particularly in older buildings that have not been upgraded.

Below is my contribution to the December 2021 issue of tED Magazine, offering another take on the new Commercial Buildings Energy Consumption Survey recently published by the Department of Energy. Reprinted with permission.

Commercial buildings in the United States are trending larger and more commonly feature LED lighting and occupancy sensors. While traditional light sources have declined in use, they remain prevalent in the nation’s estimated 5.9 million buildings, spelling a significant continuing upgrade opportunity, particularly in older buildings that have not been upgraded.

These are just some of the conclusions drawn from the U.S. Energy Information Administration’s latest Commercial Buildings Energy Consumption Survey (CBECS), which has periodically profiled the national building stock since 1979 using a survey-based approach. Published in September 2021, the 2018 report provides estimates for commercial building characteristics such as region, activity, size, age, and equipment. It follows the 2012 report, which provides an historical benchmark.

In this article, we will dig into the data to produce salient findings in two key areas: commercial building characters and lighting and controls adoption.


Between 2012 and 2018, the population of commercial buildings grew 6 percent to 5.9 million buildings, and total floorspace grew 11 percent to 97 billion sq.ft. During that time, 357,000 buildings and 7.5 billion sq.ft. were added to the national building stock. Since 1979, the amount of commercial floorspace has nearly doubled.

Other key findings:

  • By floorspace, the largest markets were office, mercantile, warehouse and storage, and education. The most common commercial building types were warehouse and storage, office, and service, representing 48 percent of buildings and 42 percent of floorspace. While common, service buildings constituted only 7 percent of floorspace.
  • The population of education, lodging, warehouse and storage, public assembly, worship, and service buildings increased. Other markets, such as office, healthcare, food sales/service, and mercantile decreased.
  • The largest population of commercial buildings and floorspace was in the South Census Region. The second was the Midwest, followed by the West (populated by buildings of the largest median size), and Northeast (smallest population of buildings, oldest in median years).
  • Newer commercial buildings tended to be larger than older buildings. In 2018, the median building size was 5,400 sq.ft., up from 5,000 sq.ft. in 2012. Seventy percent of buildings were 10,000 sq.ft. or smaller in 2018, down from about 75 percent in 2012.
  • The largest buildings were a small fraction of the building population but a third of floorspace. Buildings larger than 100,000 sq.ft. constituted only 2.4 percent of the building population but 34 percent of floorspace. In contrast, the smallest buildings—1,001 to 5,000 sq.ft.—represented nearly half of buildings but only 8 percent of floorspace.
  • The median year of construction for all U.S. commercial buildings was 1982, producing a median age of 36 years. Seventy-five percent of buildings were built on or before 2000, representing 71 percent of floorspace. Forty-six percent of all buildings, accounting for 41 percent of all floorspace, were built before 1980.
  • A total of 86 million people worked in U.S. commercial buildings. This translated to a median floorspace of 1,175 sq.ft. per worker, a 14 percent increase in space over 2012.

Lighting and controls

Compared to the 2012 survey, the 2018 CBECS shows a remarkable technological shift toward LED adoption at the expense of traditional lighting. It also reveals growing adoption of automatic lighting controls, notably occupancy sensors. Nonetheless, the continuing prevalence of traditional and uncontrolled lighting produces a snapshot of a continuing market opportunity to upgrade older lighting systems.

Key findings:

  • Adoption of LED lighting grew significantly between 2012 and 2018 in commercial buildings to become the second-most common light source. In 2018, LED lighting was used in 44 percent of commercial buildings and 64 percent of floorspace, up from 9 percent of buildings and 25 percent of floorspace in 2012. By 2018, LED was installed in 2.6 million buildings, more than five times more buildings than in 2012, and covered 62 billion sq.ft., more than two and a half times the floorspace. Looking at five major building types, adoption was highest in healthcare, mercantile, and office, as shown in Table 1.
  • Standard fluorescent remained dominant but was in decline. In 2018, standard fluorescent lighting was used in 68 percent of commercial buildings and 76 percent of total floorspace, a decline from 84 percent of buildings and 92 percent of floorspace in 2012.
  • Other traditional sources showed sharp declines in use. From 2012 to 2018, incandescent declined from 33 to 19 percent of buildings, compact fluorescent from 41 to 19 percent, halogen from 16 to 9 percent, and high-intensity discharge (HID) from 9 to 4 percent. In terms of floorspace, from 2012 to 2018, incandescent declined from 44 to 22 percent, compact fluorescent from 62 to 35 percent, halogen from 32 to 15 percent, and HID from 27 to 12 percent.

Table 1. Lighting equipment adoption in 2018 by major building type, expressed as a percentage of floorspace in that vertical market.

Office Mercantile Education All health care
Incandescent 10% 21% 35% 17% 33%
Standard fluorescent 66% 79% 83% 83% 84%
Compact fluorescent 17% 44% 52% 31% 59%
High-intensity discharge (HID) 11% 10% 9% 14% 21%
Halogen 7% 13% 35% 12% 27%
LED 47% 74% 75% 63% 77%
  • Occupancy sensor adoption significantly increased. In 2018, occupancy sensors were installed in more than 44 billion sq.ft. in more than 1 million buildings, 26 percent more buildings than in 2012 and 24 percent more floorspace. In 2018, occupancy sensors controlled lighting in 17 percent of buildings but 46 percent of total floorspace, up from and 15 percent of buildings and 41 percent of floorspace in 2012.
  • Adoption of other lighting control equipment was a mixed bag. Daylight harvesting increased from 7 to 7.5 percent of floorspace, increasing from 6.1 to 7.2 billion sq.ft. in 138,000 buildings, but remained flat at about 7 percent of floorspace. Building automation systems for lighting increased from 14 to 17 percent of floorspace, increasing from 12 to 16.7 billion sq.ft. in 317,000 buildings. Light scheduling remained flat at about 35 percent of floorspace. Multilevel lighting and dimming declined from 17 to 15 percent of floorspace, which is somewhat surprising due to the inherent controllability of LED lighting and its utility. Demand-responsive lighting significantly declined from 5 to 2 percent of floorspace. Look at the major building types in Table 2, however, adoption is nonetheless substantial for many of these equipment types in terms of controlled floorspace.
  • Plug load control remained relatively rare. In 2018, for the first time CBECS included plug load control, which showed adoption in less than 1 percent of buildings and around 2 percent of floorspace. This is expected to increase due to this strategy being included in the latest generation of commercial building energy codes.

Table 2. Lighting controls adoption in 2018 by major building type, expressed as a percentage of floorspace in that vertical market.

Office Mercantile Education Health care
Light scheduling 16% 46% 65% 35% 44%
Occupancy sensors 40% 62% 49% 57% 70%
Multi-level lighting or dimming 4% 21% 16% 15% 29%
Daylight harvesting 2% 15% 13% 6% 14%
Building automation system (BAS) for lighting 5% 22% 40% 24% 22%

While these adoption gains are impressive from an energy efficiency standpoint, inverting these numbers reveals a strong ongoing lighting upgrade opportunity, particularly in the lighting controls space.

Separately, CBECS estimated buildings and square footage that received a lighting upgrade as a renovation since 2000, around the birth of the LED revolution. Looking at buildings built since 2012, around when LED began achieving mass adoption in general lighting, 82 percent of buildings and 67 percent of floorspace have not received a lighting upgrade since 2000.

This number seems odd due to the significant adoption of LED, suggesting at least some form of upgrade has taken place. At a minimum, we can look to the continuing prevalence of traditional lighting, notably standard fluorescent still in the number one spot. If every standard fluorescent lamp were suitable for upgrade, this alone would represent lighting covering four out of five square feet in seven out of 10 buildings.

All of this leads to a simple conclusion that a substantial portion of the building stock remains untapped for LED and controls upgrades.

Check out CBECS

The 2018 CBECS is available for free online as XLS files at the Energy Information Administration’s website, offering insights into the building market that can be useful for business planning. How many warehouse and storage buildings are in the South? What is the average office floorspace per worker? In what building types is LED adoption greatest?

CBECS offers an estimate for these and many other questions here.

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Farewell Message by Craig DiLouie

It has been my privilege and honor to deliver lighting news and opinion for the past 20 years at LightNOW.

Hello, reader! Okay, this isn’t strictly a farewell, as I’ll still be contributing to LightNOW, but I have stepped down as its editor.

It has been my privilege and honor to deliver lighting news and opinion for the past 20 years at LightNOW, one of the first things I started doing after leaving ARCHITECTURAL LIGHTING back in 2001. During that time, LightNOW chronicled major changes in the industry, notably a technological shift to LED lighting and advanced controls. It’s been a wild ride for a previously staid industry, and staying informed has never been more important.

Codes, standards, regulations, products, people, metrics, construction news, awards, opinion, how-to guidance, it’s all here at LightNOW, every day, archived. Since 2013, when we switched to WordPress, LightNOW posted more than 4,250 times, each item something useful for lighting practitioners.

As for me, again, I’ll remain a contributor to LightNOW while also continuing to support other industry stalwarts such as the Lighting Controls Association, NALMCO, ELECTRICAL CONTRACTOR, tED Magazine, and other organizations, publications, and manufacturers. But I’m excited about Suelynn and David Shiller taking the editorial and publishing reins and guiding the site and newsletter to new heights with fresh insight and energy.

So thank you for visiting and reading LightNOW, and congratulations to Suelynn and David!

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Recommended Methods for Subjective Evaluation of Color Rendition

A new study funded by the Department of Energy and published in Lighting Research and Technology reviews the commonly used psychophysical experimental techniques for investigating color rendition, where human participants are asked to evaluate various subjective aspects of the color appearance of objects, such as color preference, naturalness, or vividness.

Color rendition describes the influence of light source spectrum on the color appearance of objects. The rendering of object colors in desirable ways has attracted much attention as LEDs have developed as a versatile and efficient lighting technology, with significant research effort to understand human perception and develop new metrics. These have helped manufacturers optimize LED lighting products, increasing both energy efficiency and appeal to drive adoption in workplaces and homes.

Spectrally tunable LED-based lighting is one large and growing segment of emerging products, which has also facilitated new experimental techniques. However, the increased interest and ease of experimentation has not necessarily translated into improved research quality, a more diverse range of experiments, more definitive findings, or increased use of efficient, high-quality LED products. Instead, the collective body of work has sometimes employed questionable methods that produce contradictory and, at times, overgeneralized results.

A new study funded by the Department of Energy and published in Lighting Research and Technology reviews the commonly used psychophysical experimental techniques for investigating color rendition, where human participants are asked to evaluate various subjective aspects of the color appearance of objects, such as color preference, naturalness, or vividness. The work was undertaken to encourage exceptional practices in the conceptualization, design, implementation, analysis, and reporting of such experiments. It is intended to accelerate research progress and the resulting improvements in lighting quality and energy efficiency.

The article synthesizes a large body of evidence on research methods, tailoring the solutions to the specific field using examples. Common pitfalls of existing color rendition research include a lack of clear hypotheses, failing to control for all lighting variables, insufficient adaptation, poor sampling of possible color rendition characteristics, and small sample sizes with insufficient statistical rigor. The study outlines a range of possible work to improve future methods and concludes with a list of recommended practices relevant to performing research on subjective evaluations of color rendition, which may be used as checklist by researchers, reviewers, and readers.

According to Dr. Yoshi Ohno, NIST Fellow at the National Institute of Standards and Technology, who was not involved in this study, there is still much room to improve the color quality of white LED sources for lighting preferences in different applications while ensuring the best use of energy. “Vision experiments are essential to make progress in research for this effort,” he says, “and this article by PNNL covers the whole range of important topics and recommendations for designing and conducting such vision experiments with subjects. It will be very useful for all researchers working in this area toward establishing good recommendations on color quality of LED sources for lighting.”

Download the full report.

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