The most recent Department of Energy study of commercial spaces indicated that lighting consumed 39% of the electricity in those buildings. For this reason, many people have made investments in high-efficiency light sources. However, the typical quest for energy savings can fail to take into account other important needs such as quality of light, occupant comfort and productivity. In this article, we will go beyond the simple light source change-out and look at an array of strategies that save energy without those compromises.

The concepts are sorted into broad categories to allow the reader to focus on the ideas that are most relevant. The first section covers easy upgrades that can be made to almost any building. The next section explores options that should be considered if the building has a somewhat modern but underexploited lighting control system in place. The final section applies to situations where a sizeable budget has been allocated to modernizing building control systems.

Minor Additions that Help Save Energy

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% will reduce energy consumption by 20% and will make the bulb last 4 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.

Consider Next-generation 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. What's more, energy savings derived from having lights on only 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.

Install 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.

Optimizing an Existing Lighting Control System

If the lighting control system is no longer configured to meet the original design intent, recommissioning may be the best solution. For facility managers that want to take a more incremental approach, the suggestions below 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. For those who are unfamiliar with timeclock operation, a brief explanation follows: 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%. This change will lock in savings and will increase bulb life (as described above) 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.

Conclusion

Whatever actions you choose, make sure to capitalize on rebates and other incentives. 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.

The strategies presented can produce major savings without reducing occupant comfort. One such example is The New York Times Company's new headquarters. Originally designed to use 1.28 watts per square foot, the inclusion of a total light management system has resulted in usage of only 0.38 watts per square foot. This produced a 70 percent reduction in electrical consumption, savings of $315,100 per year, and considerable recognition for a commitment to preserving the environment.

There is a tremendous range of options 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. Regardless of which changes you choose, there is no better time to start than today.

About the author: Glen Kruse is the Director of Commercial Solutions and Services at Lutron Electronics Co., Inc.