Jim Brodrick on Dimming LEDs with Phase-Cut Dimmers

Republication of Postings from the U.S. Department of Energy (DOE) Solid-State Lighting Program

by Jim Brodrick, SSL Program Manager, U.S. Department of Energy

You may recall that last year, DOE’s GATEWAY program released a report entitled Dimming LEDs with Phase-Cut Dimmers: The Specifier’s Process for Maximizing Success, which was created in response to issues raised about LED dimming by energy-efficiency organizations and specifiers, and was based on experience from CALiPER testing and GATEWAY demonstrations. That report was recently revised to include updated information on a GATEWAY demonstration involving the installation of LED lighting and controls at the Burden Museum in Troy, NY. The new information is very instructive.

The LED lighting — which ranged from dedicated track lighting for displays, to strip lighting in coves for uplighting the sculptural cherry-paneled ceiling, to period white globe chandeliers with A-lamps and amber rings to simulate the glow of gaslight — and controls were installed at the Burden in early 2014. Because of delays, which are quite common in architectural projects such as this one, the lighting designer rechecked the specifications. In the 18 months that had elapsed since those specifications were devised, several LED lighting products had been discontinued or redesigned, which necessitated changing the specifications and then rechecking all affected dimming zones.

In some cases, the replacement product resulted in more LED watts on the dimming zone, and this higher dimming load required a power module interface (an electrical device mounted between the dimmer and the load) to increase the dimming zone’s capacity. In other cases, the compatibility tables showed that the new LED products had a higher effective power draw (probably due to repetitive peak currents), so the load exceeded the dimmer’s capacity. Power module interfaces solved this issue as well, effectively increasing the capacity of the dimming circuit. In another case, manufacturer information showed that the changed LED product was more compatible with a forward-phase dimmer type than with a reverse-phase dimmer type, so the specification for the dimmer model was changed. The controls manufacturer worked closely with the lighting designer and the electrical engineer to ensure full compatibility on all the dimming circuits.

The specified control system was checked and ordered by a controls integrator, who worked as a subcontractor to the electrical contractor on this project. The integrator worked directly with the contractor during the installation, and commissioned the completed system to ensure that it operated as specified. Part of the integrator’s function was to keep track of design issues and changes that evolved during the project. For example, late in the project the original hard-wired control system was changed to a wireless system as that product became available, which dramatically reduced the cost of installing the wiring in the building.


Installation of the lighting and controls went smoothly, once the lighting designer made the necessary changes to the plans and specifications. The contractor was delighted that only three 20A electrical circuits were required for the entire project, and was impressed by how bright the LED lights were, given the low wattage. The controls integrator helped the contractor understand and install the control system, including the effective derating of load capacity on the control zones, and advised installing deeper switch boxes to make wiring easier, and following vertical and horizontal spacing recommendations for mounting power module interfaces between the dimmers and loads.

Museum staff members were thrilled with the visual appearance of the LED lighting, the remarkable range of dimming control, the ability to demonstrate different scenarios with one touch in a tablet or smartphone app, and the ease with which different scenes could be programmed.

The end result was that the process for checking LED product compatibility with phase-cut dimmers specified for each dimming zone worked very well. Although it added time to the design process, with a recheck and adjustments to the dimming specifications just before bidding and ordering products, none of the dimming circuits produced erratic or unexpected behavior once installed. Museum staff reported that all of the dimmable LED products dimmed smoothly to low levels.

The design costs using the LED system were higher than expected, because of redesign costs just before the project bid and also because there were multiple mockups to visually check LED luminaire performance and compatibility with the dimming system. Because the LEDs were new products to all parties on the design and construction team, nobody was familiar with the equipment, the catalog numbers, or LED installation issues. Pushing the envelope in technology can result in additional learning time and multiple iterations with luminaire and controls orders, for example, but all parties involved considered the project an invaluable experience that will reduce needed time on future LED projects.

For more details about this pioneering LED lighting project, see the full report here.

DOE Publishes Revised Report on Dimming LEDs with Phase-Cut Dimmers

The U.S. Department of Energy has revised its October 2013 report, Dimming LEDs with Phase-Cut Dimmers: The Specifier’s Process for Maximizing Success, to include updated information about the installation of LED lighting and controls at the Burden Museum in Troy, NY, a GATEWAY project that was still in construction when the original report was published.

Because of project delays, the lighting designer rechecked the 18-month-old specifications just before the electrical contractor ordered the lighting for the museum. Because several LED products had been discontinued or changed chip generation or driver design, some product makes and models had to be changed, which affected either the type of compatible dimmer or the number of lamps or luminaires that could be dimmed on a single dimming zone. Fortunately, the controls manufacturer worked closely with the lighting designer and electrical engineer to ensure full compatibility on all of the dimming circuits.

The lighting and controls were installed at the museum in early 2014. The end result was that the process for checking LED product compatibility with phase-cut dimmers specified for each dimming zone worked very well. Although it added time to the design process, with a recheck and adjustments to the dimming specifications just before bidding and ordering products, none of the dimming circuits produced erratic or unexpected behavior once installed.

The museum staff reported that all of the dimmable LED products dimmed smoothly to low levels. They were thrilled with the visual appearance of the LED lighting, the remarkable range of dimming control, and the ability to demonstrate different scenarios with one touch in an iPad or iPhone app.

Click here to get the report.

Navigant Report Evaluates Market for LED Streetlighting Controls

iconFrom the Navigant website:

Falling prices for light-emitting diode (LED) street lights have spurred a global transition from older lamp technologies to the newer, more efficient, and more controllable lamp technology. Prices for LED street lighting have come down to the point where payback periods are becoming reasonable with or without subsidies. Residents in cities worldwide are appreciating the improved nighttime visibility provided by the whiter light of LED street lights. Meanwhile, city managers are enjoying the cost savings that come from the resulting reduction in both energy consumption and maintenance costs.

Although the LED transition is in large part driving the adoption of new networked street light systems, most LED upgrades continue to be completed without any additional controls beyond simple photocells. After years of pilot control projects, however, a growing number of large-scale networked systems have proven that networked systems can work and can provide real benefits. These smart street lighting systems can provide substantial energy savings and a host of non-energy benefits. Yet, as LED prices continue to erode and the long lifespan of LED lamps results in fewer replacements, overall revenue from street lighting will begin to fall. Navigant Research forecasts that global street lighting revenue will decline from $2.5 billion in 2014 to $2.3 billion in 2023.

This Navigant Research report analyzes the global market for roadway and highway lighting. The study provides an analysis of the market issues, including drivers and trends, barriers, and ownership models, associated with lamps, luminaires, and lighting controls in these street lighting applications. Global market forecasts for unit sales and revenue, segmented by region, application, and equipment and construction type, extend through 2023. The report also examines the key codes, standards, and technologies related to street lighting, as well as the competitive landscape.

Key Questions Addressed:

* How do changing codes and regulations around street lighting affect the adoption of LED lamps and lighting controls?
* What are some potential ways to address the barriers hindering the adoption of street lighting controls?
* What are the advantages and disadvantages of different lighting control and communications strategies?
* Which companies are developing innovative new lighting products and techniques for city managers?
* How quickly will LED lamps be adopted on roadways and highways?
* What is the outlook for lamps, luminaires, and lighting control equipment and software in each world region?
* How are various established and startup companies positioned for success in the lighting controls market?

Click here to learn more.

LCA TV: WattStopper at LIGHTFAIR 2014

This WattStopper video presents the company’s offerings at LIGHTFAIR 2014.

What’s New in ASHRAE/IES 90.1-2013

untitledASHRAE/IES Standard 90.1 provides a model commercial building energy code that can be adopted by states and other jurisdictions. The Department of Energy recognizes the 2010 version as the national energy reference standard. The International Energy Conservation Code recognizes 90.1 as an alternate compliance standard.

The standard, which applies to new construction and major renovations (including requirements for lamp-ballast retrofits), is updated every three years. ASHRAE published the latest version in October 2013. The lighting section of ASHRAE/IES 90.1 has become increasingly sophisticated over the past 14 years, particularly in regard to lighting controls. The 2013 standard attempts to go even further while simplifying understanding and application.

What’s new? The major changes to ASHRAE/IES 90.1 2013’s Section 9 (lighting) include:

• adjusted lighting power densities (LPD)
• more stringent lighting control requirements
• a new table format for determining lighting power and control requirements in individual spaces

First, let’s look at LPD values, most of which were adjusted. For example, Building Area Method LPDs were adjusted for hospitals (down from 1.21W/ft2 to 1.05), office (up from 0.9W/ft2 to 1.01), retail (down from 1.4W/ft2 to 0.9), schools/universities (up from 0.99W/ft2 to 1.05), and warehouse buildings (up from 0.66W/ft2 to 1.01).

These adjustments save power where possible according to new light level recommendations published by the Illuminating Engineering Society (IES).

Status of adoption of commercial building energy codes as of August 2014. Source:

Status of adoption of commercial building energy codes as of August 2014. Source:

Lighting controls got a significant makeover in the 2013 standard:

• Occupancy sensors must be set to turn the lights off within 20 minutes (instead of 30 minutes) after a space is vacated.

• Automatic independent control is now required in secondary sidelighted daylight zones (covering additional luminaires farther from the windows) rather than just incentivized with a control credit.

• Daylight harvesting step-dimming control now requires two control points between off and full-on—one dim level between 50–70 percent of design power and one between 20–40 percent—to provide greater flexibility.

• A second automatic lighting shutoff option is required for certain occupancy sensor installations—partial-off to 50 percent of design power within 20 minutes of the space being vacated—spaces where the lights are periodically not needed but must remain ON.

• More detailed functional testing requirements are imposed.

The primary change in ASHRAE/IES 90.1-2013 is a new table (Table 9.6.1) format for determining LPD allowances using the space by space method and minimum mandatory control requirements using either the space by space method or building area method.

The table was developed to simplify reading and reference of LPD and control requirements in each space, but, at first glance, it may appear confusing. One must read the accompanying text as separate requirements and options applicable to the table, not a consecutive list of actual requirements. Otherwise, proper use of the table is in the fine print. For example, two tables actually list space types, but the first represents space types commonly found in multiple building types, while the second covers space types typically found in a single building type.

For open offices, the LPD is 0.98 if using the space by space method. The room cavity ratio (RCR) threshold is 4, meaning an additional lighting power allowance of 20 percent is available if the actual RCR (2.5 × room cavity height × room perimeter length ÷ room area) exceeds the threshold. Various controls are then required, and some choices are available. For example, in open offices, space controls are required to give users control over their lighting. All lighting must be capable of bilevel control. If daylight is present, lighting in the daylight zones must be separately and automatically controlled. The lights may be manual-on (“ADD1”) or partial-automatic-on (“ADD1”), and they must be turned off automatically based on occupancy (“ADD2”) or a schedule (“ADD2”).

The U.S. Department of Energy (DOE) recently concluded that the 2013 standard saves 7.6 percent site energy over the 2010 standard, the first step in issuing a ruling that could establish the 2013 standard as the national energy reference standard for state building energy codes.

If the preliminary determination is finalized, then states would be required to update their codes to meet or exceed the 2013 standard.

NCL Showroom Wins IES Lighting Control Innovation Award Of Merit

The Lighting Control Innovation Award was created in 2011 as part of the Illuminating Engineering Society’s Illumination Awards program, which recognizes professionalism, ingenuity and originality in lighting design. LCA is proud to sponsor the Lighting Control Innovation Award, which recognizes projects that exemplify the effective application of lighting controls in nonresidential spaces.

This month, we will explore the role that lighting controls play in enhancing the visitor experience at a high-end lighting showroom. Lighting and control design by Alexander Shaw, Lighting Designer, Nouran Concept Lighting. Photography by Alia Al Shaz. Lighting controls by Beckhoff.

This showroom is dedicated to the exhibition of high-end lighting fixtures. The concept for the lighting design focused on a “lighting experience”, where visitors are drawn to a physical and perceptual encounter with lighting products and ideas.


The interior was inspired on an industrial chic aesthetic. White textile walls modulate the space, creating corridors which resemble a traditional Arabic town. Surprise and discovery are the key elements. This provides the perfect background to showcase a variety of lighting elements.


These textile walls were equipped with RGB sources to become dynamic color objects, capable of flooding the room with the most incredible saturated colors, changing the mood of the store in a matter of seconds.


Cool white, amber and blue Led dots are activated by motion sensors when visitors enter the “outdoor” area. These, together with a blue hue from the walls, create an inviting moonlit atmosphere.



The entire showroom is DALI controlled, enabling the creation of scenes based on customers’ behaviors and commands. e.g. motion sensors located at the entrance of corridors trigger a sequence of light dots on the floor, inviting to explore further.


By default all chandeliers are off, creating a silhouette effect against the lit wall.


Fixtures are touchpad controlled, allowing customers to switch on the desired product, dimming down the wall behind to increase contrast. Upon activation, the screen displays relevant fixture information (images, dimensions, specifications and related products).


The application also allows to shift between scenes or manually control the wall colors.


Keyboard screen for fixture selection.


A smart automation criteria allowed great energy reduction. Fixtures are off by default but still the space looks intriguing and welcoming due to the lit walls. The wireless touchpads reduced conduiting and cabling costs and allowed flexibility for future store layouts.

LCA TV: Roller 300 with Intelligent Face Technology by Lutron

This short video, produced by the Lighting Controls Association at the 2013 LIGHTFAIR event, introduces the building industry to Lutron Electronics’ Roller 300 with Intelligent Facade Technology.

Schneider Electric Unveils Product Selection Tool

schneider electric new tool-2Schneider Electric Lighting Controls Division recently unveiled a new generation of product-selection tools. This mobile-friendly online solution selector finds the best code-compliant lighting control solutions for any room in just seconds. Users can then save selected applications for multiple rooms and building projects in a login-protected portfolio. The new Lighting Controls Application Guide saves time and increase accuracy in product selection. There are already over 100 code compliant pre-determined solutions; the company is adding more on an ongoing basis.

Click here to try out Schneider Electric’s all-new online application guide.

Universal Lighting Technologies Wins Two “Best of the Best” Awards from TED Magazine

Universal Lighting Technologies was recently recognized in tED Magazine’s “Best of the Best” Awards for 2014. The Nashville-based lighting company’s marketing efforts won in two categories: digital and social media campaign for a supplier under $250 million and website for a supplier under $250 million. The winners were announced at the NAED AdVenture Conference in Chicago on August 5.

The annual marketing awards competition hosted by tED Magazine honors marketing excellence and recognizes creativity within the electrical industry in companies of all sizes across several marketing and communications categories. Entries are judged on their overall effectiveness and creative impact by an independent panel of marketing and industry professionals secured by tED Magazine. 

Click here to learn more about Universal Lighting Technologies.

Office Workers Want More Control of Their Lighting

A study by Zumtobel and the Fraunhofer Institute for Industrial Engineering indicates that office workers prefer brighter light sources they can control in terms of both intensity and color temperature. has the story here.