Lighting uses more electricity than any other building system, according to the most recent study from the Department of Energy’s Energy Information Administration. At 38 percent of total electricity usage, the lights in a commercial building typically use nearly triple the next biggest draw, cooling (13 percent). Facilities often address the issue by turning to more efficient light sources — compact fluorescent lamps for task lighting, fluorescent fixtures for general lighting — but stopping there is only half the solution. Without controlling the lighting, spaces are left over-lit, which results in wasted energy and money and less comfortable, productive, and attractive spaces.

A thoughtfully deployed lighting control system simultaneously addresses two challenges critical to the development and maintenance of a sustainable facility: reduced energy usage and occupant comfort. Lighting control saves energy by turning off or dimming lights according to any number of criteria, including time of day, unoccupied spaces, the presence of adequate daylight, load shed requests from the utility company or simple occupant control. Light control creates a more comfortable and productive space by reducing screen glare and eye strain, by using electronic shading to limit solar heat gain and hot spots, and by giving the people in a space the power to set lighting to the levels they prefer.

The results of quality light control can be dramatic. The light control system at The New York Times Co. building in Manhattan, for example, is reporting lighting energy savings exceeding 70 percent (See SF, Feb. 2009). The historic Bently Reserve in San Francisco recently completed a major renovation and its light control system is saving 60 percent. Sidwell Friends School in Washington, D.C., Exelon headquarters in Chicago, and SCA Americas at the Cira Center in Philadelphia all report dramatic energy savings as well. And in each space, emphasis is placed on creating a dynamic, productive and healthy interior environment in which the light control system plays a key role.

Light control is an easy retrofit. By taking advantage of new wireless and scalable technology, facility managers can deliver immediate energy savings without the cost of time spent rewiring. Consider some of the light control strategies that get it done.

Quick fixes

Control All Incandescent Bulbs with Dimmers

In high-end conference rooms and restaurants, an incandescent light source is still very popular because of its excellent light quality. Controlling those lights with dimmers will save energy and extend the life of the light bulbs. For example, setting the light level to 75 percent will reduce energy consumption by 20 percent and will make the bulb last four times longer. The savings on bulb maintenance more than pays for the dimmer, so any energy saved is a bonus. The dimmer will also improve the ambiance in the room by allowing the occupants to select the preferred light level.

Install Wireless Occupancy Sensors

Some facility managers are reluctant to consider using occupancy sensors because first-generation sensors were unreliable and limited in capability. However, modern sensors can work in a wide variety of applications, feature reliable sensing technology, and have configurable timeouts and modes that allow them to be tailored to the specific needs of the space. Additionally, energy savings derived from having lights only being on when a space is occupied can be significant. The latest sensor solutions use radio frequency (RF) technology that eliminates the need to change wiring, allowing these sensor solutions to be installed in minutes.

Put Lights on Timers

You may remember the loud, cumbersome, twist-to-turn-on timers that were used to automatically turn off lights and fans after a predetermined interval. For applications where timer functionality is preferred to sensors, modern and user-friendly tap-on timers are now available. 

Re-commissioning

If the lighting control system is no longer configured to meet the original design intent, re-commissioning may be the best solution. For facility managers who want to take a more incremental approach, the following suggestions can help increase savings with less time investment.

Fully Utilize Timeclock Capabilities

Most lighting control systems have the capability to turn lights on and off automatically according to the time of day. Significant savings can be realized by taking a fresh look at the timeclock programming and confirming that it is best supporting the building’s needs. You can create a schedule for each day of the week that defines what time lights turn on (and to what light level) and turn off. Systems with astronomic timeclocks control lights relative to sunrise and sunset rather than a specific time of day, so the timeclock actions automatically adjust to seasonal changes. A combination of an astronomic event and a fixed-time event is particularly useful for exterior spaces or public areas with many windows. For example, entrance lights can be programmed to turn on 15 minutes before sunset and turn off at midnight.

Adjust Maximum Light Output

Most buildings have fixtures with dimmable light sources capable of providing more light output than is truly needed by the occupants. Many lighting systems have a “high-end trim” feature, which enables you to limit the maximum light level to a value of less than 100 percent. This change will lock in savings and will increase bulb life (as previously described) for many common light sources. This change should be made at the same time as any timeclock adjustments.

Reduce Lighting Usage with Load Shed

If your building has a more sophisticated system that offers a load shed feature, you may be able to get rebates or lower rates from your electricity supplier. The load shed feature allows users to reduce power consumption at the request of the utility; configuration of the load shed feature or training on how to use it is not time consuming and can result in substantial savings.

Evaluate System Programming Regularly

Offices and people move around as needs change, and with new occupants come new requirements for light levels. To avoid unhappy employees and customers, it is a good idea to routinely check all parameters of the lighting system to ensure alignment with the building’s current use. Keep all of the tips above in mind when completing routine check-ups. 

Facility Modernization

Upgrade or Replace an Out-of-Date System

An updated system brings advanced control features and energy-saving capabilities to an older building. In most cases, a system can be upgraded to modern technology without significant facility rewiring or major disruption to everyday business. A state-of-the-art system can include all of the features and strategies explained within this article.

Maximize Use of Daylight

If considering a new system, look at the opportunity to utilize natural light to the greatest extent possible. Daylight sensors allow a lighting system to automatically reduce artificial light output when natural light is available. Smooth lighting transitions go unnoticed by occupants while yielding substantial savings.

Automate Shade Movements

Controllable shading systems can further exploit natural light without exposing occupants to unwanted glare. Systems that control the movement of shades in conjunction with artificial lighting provide consistent lighting throughout the day. Solar-adaptive shading systems improve the aesthetics of the space by providing a view of the outdoors at times when the sunlight is not overpowering.

Monitor and Display Lighting Energy Usage

Systems that record energy consumption give you the ability to fine-tune lighting usage to maximize savings. When real-time energy savings data is available from the system, that information can be displayed publicly to reinforce your company’s commitment to conservation. This can motivate employees and visitors to modify their actions to further improve those savings.

Based upon facility location and the scope of the improvement, you may be eligible to receive incentives such as tax credits, utility rebates, or federal stimulus monies that encourage energy efficiency. Facility owners can find out if their renovations are eligible for utility rebates by contacting their electric company. Information on tax credits and stimulus programs can be found on government websites.

A tremendous range of options exist when it comes to optimizing energy use. You should keep a few things in mind during your quest to choose among them: make sure you understand all of the implications of a given option, and choose the solutions that best complement the mission of your facility, even if they aren’t the ones that save the most energy.