Automated Lighting Controls Keep Costs Down

“By learning the advanced features and emerging applications for these devices, electrical contractors can enhance their competitiveness by being able to correctly install, program and commission lighting controls,” says Craig DiLouie, communications director of the Lighting Controls Association (LCA) in Rosslyn, Va. Learning to install more sophisticated applications can increase a contractor’s revenues, he adds.

Save with Sensors
Occupancy sensors detect human presence and turn lights on and off accordingly. They work best in common spaces—such as conference spaces, storage areas, restrooms or laundry, workout and break rooms—where people are less likely to be turn off lights manually, says Liesel Whitney-Schulte, business program lighting project manager for Focus on Energy, Wisconsin's energy efficiency and renewable energy initiative that helps residents and businesses install cost-effective energy efficiency and renewable energy projects. “People don’t feel the ownership of space in common areas with intermittent use, so they don’t feel the need to turn the lights off when they leave,” she says.

Energy savings from occupancy sensors vary widely—13 to 90 percent, according to U.S. Environmental Protection Agency (EPA) estimates—depending on the particular sensor and how the space is used. These types of controls are “generally considered an economical and reliable way to turn the lights off when they are not needed in use, thereby producing satisfying levels of energy savings,” DiLouie says.

There are basically two types of occupancy sensor technology: passive infrared (PIR) and ultrasonic. PIR sensors turn a light on when they detect temperature changes in a room, such as the heat generated by people walking into a space. They work best in smaller spaces; they generally have a 15-foot range.

Ultrasonic sensors “work like a bat” by sending out high frequency sound signals to detect motion and “see” around obstacles and corners, Whitney-Schulte says. Because they emit a signal, ultrasonic sensors are best utilized in large spaces, but both types may be prone to false triggering. Dual-technology sensors are generally more effective, and more expensive as well, because they incorporate both infrared and ultrasonic technologies.

Each type has its advantages in different applications, so helping your customer choose the right one is important. “It’s a bad result if it’s the wrong one because it might trip all the time or never trip,” she says.

Scheduled Shut-offs
Automatic time-scheduling lighting controls are calibrated to switch lights on or off on a set schedule. These types of switching controls are great for offices or other places of business with set operating hours. They’re also flexible—users can turn the lights on manually if they still need them after they have shut off. Even more energy can be saved if the controls are scheduled so the lights are turned on manually in the morning when the first employees arrive, so no energy is being wasted.

Using scheduled automatic shut-off technology can save a building 5 to 10 percent of its energy usage per kilowatt-hour (kWh) during peak periods, according to the California Energy Commission.

Dim the Lights, Control the Costs
Because of their high flexibility and the potential for energy savings, dimming controls are gaining in popularity. Dimming controls can be operated manually to support visual needs, a common solution in homes and offices, or automatically to save energy using daylight dimming or scheduling strategies.

Energy savings from daylight dimming can range from 35 to 60 percent depending on the application, according to the Advanced Lighting Guidelines: 2003 Edition from the New Buildings Institute.

Dimming has significant potential as a load-shedding or demand-response strategy, as users can reduce load during peak demand periods without turning essential lighting off while in use, DiLouie says. “Fluorescent dimming is on the rise for several reasons, including the increased use of daylighting, which presents opportunities for daylight harvesting,” he says. “Dimming controls can present a higher initial cost but can save significant amounts of energy, depending on the application and provide the ultimate in lighting flexibility for users.”

Automatic daylight-dimming installations work best in private offices, corridors or other spaces near windows. As with all automatic lighting controls, correct calibration is necessary to ensure users get the lighting they need while maximizing energy savings.

In the residential market, demand for dimming controls has been trending upward strongly. “In a residential application, customer needs and wants tend to focus less on energy savings and more on lifestyle and convenience,” DiLouie says. “In the home, dimming can create a certain desired mood or atmosphere, or support certain visual needs, while switching can be programmed or centrally controlled.”