Resources Category

Lighting Controls

High-efficiency light sources, such as fluorescent and LED, provide energy and cost savings when they are controlled in a smart way that minimizes or eliminates the use of extraneous electric light. Without control infrastructure in place to shut off fixtures when their light is not needed, unoccupied or amply daylight spaces are often artificially, and needlessly, illuminated.

LIGHTING CONTROL STRATEGIES
Design teams can choose from a variety of different lighting control strategies with the potential to yield substantial energy savings. Some approaches are very common, while others are relatively new and may require the implementation of advanced control systems. The following paragraphs introduce eight fundamental lighting control strategies that can be combined in various ways to deliver high-quality lighting environments and energy savings.


ZONING
Zoning refers to the creation of several lighting control zones that can be independently controlled to turn on/off or dim all the luminaires within each zone. Zoning is an essential lighting control prerequisite that does not result in energy savings by itself, but that enables other control strategies to be effective. It is particularly important for larger spaces where tasks, occupancy, access to daylight, and the need for artificial light at different times may vary across the floor plate.

SMART TIME SCHEDULING
Scheduling controls save energy by turning lighting systems off during unoccupied periods based on a set daily time schedule. They are suitable for spaces with reasonably predictable occupancy patterns. Since in most cases some limited activities will still occur outside of the scheduled hours—for example space cleaning or late working employees—override switches or additional control schemes (such as dimming lights to a lower level or turning on fewer fixtures for after-hours activities) should supplement a scheduling control system.

Typical applications include open offices, retail sales floors, parking lots, and corridors. Lighting energy savings from a scheduling control system typically range from 10 to 30 percent.



OCCUPANCY AND VACANCY CONTROLS
Occupancy sensors detect occupancy of a space, typically using passive infrared technology, and save energy by automatically turning off the lights when a space is unoccupied for a given time period. They are best suited for spaces with unpredictable occupancy pattern. A newer type of occupancy sensor, called a vacancy sensor, is now specifically required in New York City for some types of space per Local Law 48. Vacancy sensors require a manual control to turn on the lights, but, just like occupancy sensors, turn off the lights automatically when the space is unoccupied. Vacancy sensors prevent lights from being turned on automatically when spaces are daylit or when electric lighting is not desired by the occupant.

Typical applications include private offices, conference rooms, classrooms, storage rooms, and warehouses. Lighting energy savings from occupancy controls is highly dependent on the specific application and can range from 15 to as much as 90 percent.


DAYLIGHT HARVESTING
Daylight harvesting controls enable the reduction of artificial lighting levels during times of available daylight. They employ photosensors to monitor interior lighting levels and reduce electric lighting levels in proportion to the available daylight. Careful attention is needed to ensure that the daylight is not accompanied by unacceptable levels of thermal heat gain and/or glare.

Typical applications include open offices, retail spaces, classrooms, and warehouses. Lighting energy savings from daylight harvesting controls typically range from 30 to 60 percent compared to full-on lighting during these periods.

The reduction of electric lighting can be accomplished either by dimming or switching. The dimming approach is preferable in workplace environments, since it avoids the sudden, noticeable turning on or off of the lights, making it more acceptable to the occupants. It also allows for steeper lighting energy reductions. The increased utilization of LED lighting will make dimming a viable option for most applications without the added cost of fluorescent dimming ballasts.

In some circumstances, however, switching may be a preferable low-cost option. Spaces with a great number of lighting zones can program incremental switched reductions that do not feel too disruptive to the occupants. Energy savings are almost always smaller than those realized by a continuous dimming system though. The following diagram illustrates the energy savings advantage of a continuous dimming system over a switching approach for a 8am to noon period.


PERSONAL DIMMING AND TUNING
Dimmable lighting fixtures that can be controlled by the occupants are best suited for lighting systems specific to individuals, such as tasklights. Such fixtures enable occupants to tune the lighting levels in their workspace to their specific needs. Office workers exhibit a wide range of light level preferences for different tasks. As with room temperature, no single setting can satisfy the preferences of all occupants. Allowing workers to adjust their own lighting environment to their liking not only leads to energy savings from reduced usage but also increases occupant satisfaction and productivity.

Typical applications include open and private offices, and all spaces receiving daylight. Lighting energy savings from personal controls typically range from 5 to 20 percent.


TASK TUNING / HIGH END TRIM
High-end trim dimming involves dimming of the lights so that only the desired amount of illumination is delivered to a task surface. This control strategy essentially eliminates “overlighting” of a space. Because this excess light is called “high end”, this type of tuning is often referred to as “high-end trim”.

High-end trim dimming can be implemented as either an active or a passive system. An active system uses a photocell that measures the illumination level on a task surface and automatically adjusts the light to provide a desired level. A passive system is less precise, as it relies on a facility manager or office occupants to adjust all lights in a zone or space to provide the desired level.

Typical applications include open and private offices, spaces with specific task surfaces and, in general, overlit spaces. Energy savings from high-end trim dimming typically range from 5 to 10 percent.


ADAPTIVE COMPENSATION
Adaptive compensation is a currently underused control strategy typically applied to spaces that operate outside of daylight hours. It is based on the premise that the human visual system needs, and in fact prefers, less light at night than during the day.

At night, when the outside environment typically has much lower illumination levels than during the day, retail stores and other facilities can reduce their interior illumination by as much as 50 percent via dimming or switching without compromising usability or safety. As a result, such spaces won’t appear overly bright compared to their surroundings and will provide an environment for workers and visitors that is “easier on the eyes.”

Typical applications include supermarkets and other retail stores, airports, building lobbies, and atria. Energy savings from adaptive compensation can be as high as 50 percent.

LOAD SHEDDING

Load shedding is a strategy that reduces lighting power based on a signal from the electric utility company (in New York City, this is generally Con Edison). Participating customers typically receive a special rate from the utility for installing the load shedding infrastructure in their building or space. During peak power periods such as hot summer days, the utility may send a signal to the customer that results in dimming of the lights by an average of 10 percent (and potentially other load shedding interventions unrelated to the lighting systems), freeing up capacity for the utility to meet the peak power demand.

Typical applications include large facilities with central control, such as large offices or large industrial plants.


SUMMARY
Deciding which control strategy or combination of strategies to implement in a particular building or space depends on the specific project circumstances. Most importantly, the physical characteristics of a space, such as floor plate geometry, interior layout, window distribution, ceiling height, etc., must be conducive to the effectiveness of the chosen strategy(ies). Furthermore, as with any other efficiency upgrade, the economic terms of implementation must be viable.

The following chart provides some general guidance on the appropriateness of the control strategies discussed above for spaces with various physical and operational characteristics.
 
THREE APPROACHES TO LIGHTING CONTROL UPGRADES
Potential lighting control upgrades can vary considerably in complexity and cost. We have labeled three tiers of upgrades from simple to complex as Good, Better, and Better Yet approaches: Good is perhaps the most common, and involves the simple component replacement of stand-alone controls to meet the requirements of the current energy code. Better involves controls replacements with a centralized control system coupled with additional energy reduction control strategies. Better Yet involves the installation of an integrated control system with multiple cost-effective energy reduction control strategies in the context of a total relighting and redesign scope.

Good - Stand-Alone Controls
Modern stand-alone controls, such as wall or ceiling-mounted occupancy/vacancy sensors or photocells, allow for some level of energy savings compared to the old standard of manual on/off light switches. These controls are typically line voltage devices and are either wired between a lighting control panel and the control switch/sensor, or between the control switch/sensor and the light fixture itself.

Stand-alone controls are cost-effective, simple devices, and since they are most often wired similar to a standard light switch, electrical contractors are already familiar with their installation. Because they cannot easily be rewired or combined with other lighting control strategies, they offer only limited flexibility once they are in place.

Better - Centralized Control System
A centralized lighting control system typically utilizes a low-voltage relay-based lighting control panel. The power wiring between the panel and the control switches/sensors is low voltage and separate from the line voltage wiring between the panel and the luminaires themselves.

This system affords a high level of flexibility as multiple layers of control can easily be integrated. Programming and monitoring can be accomplished from a central location, either from the control panel display or a connected laptop. Furthermore, the lighting control system can be integrated with a larger building automation system (BAS).

A centralized control system requires a separate low-voltage wiring infrastructure which may be unfamiliar to some electrical contractors. Although more zones and control strategies can be implemented compared to stand-alone controls, panels still limit the total number of zones and control strategies that can be programmed in.

Better Yet: Fully Integrated, Addressable Control System
The Better Yet approach consists of a fully-integrated, addressable control system enabling all viable lighting control strategies meant to achieve energy use reductions and realize high-quality (day)lighting environments. These systems can either be wired or wireless.

An example of a wired solution is a DALI ©addressable lighting system. The main components are a computer connected to a controller, usually via CAT5 network cable, low-voltage control wiring to all fixtures, and controls and sensors. Each fixture or zone is addressable and can be programmed to be connected to any control device. Zones are programmed, not defined by the wiring of the light fixtures Therefore, lighting zones can be reconfigured at any time, which is very advantageous in the event of tenant changes or other spatial reconfigurations.

More recently, wireless control systems that largely eliminate the need and associated labor and cost for wiring while still offering the benefits and flexibility of a fully addressable system have been introduced to the market. In these systems the communication between the centralized control, the individual luminaires or zones, and switches, sensors and other control components occurs wirelessly.



CHALLENGES
Many of the control strategies discussed above are relatively new and the level of familiarity with them among designers, electrical contractors, building managers, and occupants is uneven at best. These circumstances result in a number of challenges to the successful implementation of advanced lighting control strategies.

New York City is a high-labor-cost environment. Coupled with contractors’ potential lack of familiarity with advanced lighting control technology, this could lead to increased bid prices jeopardizing an attractive return on investment. Conducting pre-bid training could be a way to mitigate this risk.

Design-phase pricing of control scenarios poses another challenge. It may be difficult because shop-drawing level component lists are rarely available until the project has been bid, resulting in a level of uncertainty that may be compensated by an elevated bid price. Therefore, assessing the financial viability and attractiveness of a potential lighting controls upgrade can also be difficult.

Furthermore, any advanced lighting control concept has to consider the interaction with interior or exterior automated or manual shading devices. This is essential to keep glare and thermal heat gain within acceptable limits, yet occupants and building managers are often unfamiliar with the intricacies of the required interaction and as a result may choose to disable some or all elements of the control strategy. Proper education of managers and occupants who will have to operate and live with the system in the long term should therefore be a high priority.

WRITING A LIGHTING CONTROL INTENT NARRATIVE
Any successful lighting control strategy is the outcome of a thoughtfully designed, carefully specified control system, installed in accordance with the design and commissioned to ensure its proper functioning.

To ensure that successful outcomes are realized, a Lighting Control Intent Narrative formalizing important key parameters and strategies can serve as an essential communication and project management tool at all phases of design, construction and operation. It addresses the functionality of the space's lighting at different times, describes how each event should be triggered, and defines the mandatory controls required by the energy code. Here’s how to create and implement a successful lighting control intent narrative:
  1. Define: Start by writing, in simple, straightforward language, a description of how each space is intended to be controlled. This serves to reach a consensus on the plan of action between the design team, owner, and intended occupants.
  2. Delineate: Supplement the narrative with diagrams to indicate intended zones or groups of lights to be controlled together.
  3. Disseminate: Share the narrative with manufacturers as the basis of discussion and further refinement.
  4. Commit: Include a final version of the narrative as an integral part of the contract documents.
  5. Certify: During shop drawing review, manufacturers should state in writing that they are meeting the performance criteria established in the Lighting Control Intent Narrative.
  6. Commission: The Lighting Control Intent Narrative will assist the Commissioning Agent during final calibration. The final calibration settings should be recorded for future re-commissioning.
  7. Maintain: The Control Intent Narrative should be kept on file by the owner so that the facilities manager, occupants, and re-commissioning agent can refer to it and understand the intended operation of the lighting controls.

LIGHTING CONTROL STRATEGIES

Design teams can choose from a variety of different lighting control strategies with the potential to yield substantial energy savings. Some approaches are very common, while others are relatively new and may require the implementation of advanced control systems. The following paragraphs introduce eight fundamental lighting control strategies that can be combined in various ways to deliver high-quality lighting environments and energy savings.

Zoning
Scheduling controls save energy by turning lighting systems off during unoccupied periods based on a set daily time schedule. They are suitable for spaces with reasonably predictable occupancy patterns. Since in most cases some limited activities will still occur outside of the scheduled hours—for example space cleaning or late working employees—override switches or additional control schemes (such as dimming lights to a lower level or turning on fewer fixtures for after-hours activities) should supplement a scheduling control system.

Typical applications include open offices, retail sales floors, parking lots, and corridors. Lighting energy savings from a scheduling control system typically range from 10 to 30 percent.

Occupancy and Vacancy Controls
Occupancy sensors detect occupancy of a space, typically using passive infrared technology, and save energy by automatically turning off the lights when a space is unoccupied for a given time period. They are best suited for spaces with unpredictable occupancy pattern. A newer type of occupancy sensor, called a vacancy sensor, is now specifically required in New York City for some types of space per Local Law 48. Vacancy sensors require a manual control to turn on the lights, but, just like occupancy sensors, turn off the lights automatically when the space is unoccupied. Vacancy sensors prevent lights from being turned on automatically when spaces are daylit or when electric lighting is not desired by the occupant.

Typical applications include private offices, conference rooms, classrooms, storage rooms, and warehouses. Lighting energy savings from occupancy controls is highly dependent on the specific application and can range from 15 to as much as 90 percent.

Daylight Harvesting
Daylight harvesting controls enable the reduction of artificial lighting levels during times of available daylight. They employ photosensors to monitor interior lighting levels and reduce electric lighting levels in proportion to the available daylight. Careful attention is needed to ensure that the daylight is not accompanied by unacceptable levels of thermal heat gain and/or glare.

Typical applications include open offices, retail spaces, classrooms, and warehouses. Lighting energy savings from daylight harvesting controls typically range from 30 to 60 percent compared to full-on lighting during these periods.

The reduction of electric lighting can be accomplished either by dimming or switching. The dimming approach is preferable in workplace environments, since it avoids the sudden, noticeable turning on or off of the lights, making it more acceptable to the occupants. It also allows for steeper lighting energy reductions. The increased utilization of LED lighting will make dimming a viable option for most applications without the added cost of fluorescent dimming ballasts.

In some circumstances, however, switching may be a preferable low-cost option. Spaces with a great number of lighting zones can program incremental switched reductions that do not feel too disruptive to the occupants. Energy savings are almost always smaller than those realized by a continuous dimming system though. The following diagram illustrates the energy savings advantage of a continuous dimming system over a switching approach for a 8am to noon period.

Personal Dimming and Tuning
Dimmable lighting fixtures that can be controlled by the occupants are best suited for lighting systems specific to individuals, such as tasklights. Such fixtures enable occupants to tune the lighting levels in their workspace to their specific needs. Office workers exhibit a wide range of light level preferences for different tasks. As with room temperature, no single setting can satisfy the preferences of all occupants. Allowing workers to adjust their own lighting environment to their liking not only leads to energy savings from reduced usage but also increases occupant satisfaction and productivity.

Typical applications include open and private offices, and all spaces receiving daylight. Lighting energy savings from personal controls typically range from 5 to 20 percent.

Task Tuning/High End Trim
High-end trim dimming involves dimming of the lights so that only the desired amount of illumination is delivered to a task surface. This control strategy essentially eliminates “overlighting” of a space. Because this excess light is called “high end”, this type of tuning is often referred to as “high-end trim”.

High-end trim dimming can be implemented as either an active or a passive system. An active system uses a photocell that measures the illumination level on a task surface and automatically adjusts the light to provide a desired level. A passive system is less precise, as it relies on a facility manager or office occupants to adjust all lights in a zone or space to provide the desired level.

Typical applications include open and private offices, spaces with specific task surfaces and, in general, overlit spaces. Energy savings from high-end trim dimming typically range from 5 to 10 percent.

Adaptive Compensation
Adaptive compensation is a currently underused control strategy typically applied to spaces that operate outside of daylight hours. It is based on the premise that the human visual system needs, and in fact prefers, less light at night than during the day.

At night, when the outside environment typically has much lower illumination levels than during the day, retail stores and other facilities can reduce their interior illumination by as much as 50 percent via dimming or switching without compromising usability or safety. As a result, such spaces won’t appear overly bright compared to their surroundings and will provide an environment for workers and visitors that is “easier on the eyes.”

Typical applications include supermarkets and other retail stores, airports, building lobbies, and atria. Energy savings from adaptive compensation can be as high as 50 percent.

Load Shedding
Load shedding is a strategy that reduces lighting power based on a signal from the electric utility company (in New York City, this is generally Con Edison). Participating customers typically receive a special rate from the utility for installing the load shedding infrastructure in their building or space. During peak power periods such as hot summer days, the utility may send a signal to the customer that results in dimming of the lights by an average of 10 percent (and potentially other load shedding interventions unrelated to the lighting systems), freeing up capacity for the utility to meet the peak power demand.

Typical applications include large facilities with central control, such as large offices or large industrial plants.

SUMMARY
Deciding which control strategy or combination of strategies to implement in a particular building or space depends on the specific project circumstances. Most importantly, the physical characteristics of a space, such as floor plate geometry, interior layout, window distribution, ceiling height, etc., must be conducive to the effectiveness of the chosen strategy(ies). Furthermore, as with any other efficiency upgrade, the economic terms of implementation must be viable.

The following chart provides some general guidance on the appropriateness of the control strategies discussed above for spaces with various physical and operational characteristics.

Case Study

MechoSystems HQ Renovation

BEEx case study of a successful adaptive reuse project
Case Study

NYPA: Daylight Hour Strategies & Outcomes

A Daylight Hour case study about effective community engagement and real-time energy tracking.
Reports

The Living Lab Demonstration Project

An innovative project to advance daylighting in NYC
Reports

Let There Be Daylight

Opportunities for advanced daylighting systems in New York City
Sources

Green Light: See the Light Trainings

A 3-part course focused on lighting codes, controls and retrofits
Sources

Greener Greater Buildings Plan

Sources

Navigating BEEx Resources

Locate research, projects and information quickly
Sources

Press

BEEx in the news
Sources

Green Light Training Series

A four-part training on lighting retrofits
Sources

Lighting the Future Gallery Talks

A four-part BEEx series
Events

Lighting Controls

This is a past event.
Events

Beacon of Light

This is a past event
Events

Reflecting the Sky: A Presentation of the Fulton Transit Center Oculus

This is a past event
Events

Lighting the Nerve Center: The Related HQ Lighting Retrofit

This is a past event
Events

Illuminating Change - Living Labs for Advanced Controls

A BEEx presentation at LIGHTFAIR
Events

Daylight Metrics: The What, How, and Why Should I Care

This is a past event
Events

Lighting the Future

View past event presentation, videos, and photographs
Events

Gallery Talk: Lighting with More Function & Less Fuss

Check out the event photos
Events

Gallery Talk: Convenience & Flexibility in Lighting Systems

A Building Energy Exchange series
Events

Gallery Talk: Expandable Lighting Solutions

A Building Energy Exchange series
Events

Gallery Talk: Sensing the Future Through Lighting

A Building Energy Exchange series
Events

Green Light: Lighting Codes & Regulations

A Building Energy Exchange training series
Events

Green Light: LED Lighting - Evaluation & Selection

A Building Energy Exchange training series
Events

Green Light: Advanced Controls - Types & Functions

A Building Energy Exchange training series
Blogs

Green Light Trainings: Who & Why?

Welcome to the Building Energy Exchange! Located in downtown Manhattan, we’re a resource center dedicated to advancing efficient energy and lighting design in buildings. Explore this site for helpful case studies and reports, check out our calendar for a wide range of activities and events, and follow our lively blog, Insight. Our site is growing all the time—drop us an email to contribute or comment!

Welcome.

Enter