For the maximum amount of control, a centralized system is ideal. "In large areas, it's really not feasible for someone to go around and turn off lights in an entire building," says Ike. A centralized system can provide time scheduling functions by automating the time of day when lights are turned on and off - and even help with load shedding. "Now, people are trying to make their buildings more responsive to demand shed requirements. To be able to tell your lighting to go to lower levels throughout the building in response to [brown-out conditions] is beginning to show up on the horizon as one of those functions that adds value to the building," explains David Peterson, director, strategic market development, The Watt Stopper, Warwick, RI.
Current codes require that centralized control systems have an override function. Most systems will provide occupants with a "warning" (usually through blinking lights) to alert them that the central system will soon be shutting off lights. At this time, occupants can initiate an override using a wall switch or telephone dial-up codes.
Centralized controls can be tied into the building automation system and provide monitoring capabilities that prove beneficial. "One of the things that we worry about with standalone lighting controls is that you lose the ability to track what is actually happening in the space - to know that you are actually getting the savings that you desire, that you paid for," explains Peterson.
"A lighting control system can be installed adjacent to the existing breaker panels. And with a minor amount of rewiring, the circuitry can be rerouted through the control panel," says Baselici, of installation in existing buildings. "In a lot of cases, we can take advantage of the wire that is already in the building - either phone lines or information network wiring. While it's not that commonplace, the technology is there for us to use that wiring today." Initial cost of a centralized system is greater, extending payback to an estimated seven or eight years.
"By having that central control, you are absolutely assured of a certain level of savings every day. It gives you tremendous options," Borden says.