Automatic Shutoff Includes Occupancy Sensors, Load-Scheduling Devices
To prevent energy waste, most new commercial buildings contain some means of automatic shutoff, such as occupancy sensors or intelligent load-scheduling devices. Occupancy sensors can deliver 35-45 percent energy savings in offices, while load scheduling can produce energy savings of 5-15 percent.
When using energy codes or the LEED for Existing Buildings rating system, automatic shutoff is a fundamental energy-saving solution that ensures lights turn off when not in use. These strategies also generally are considered the easiest to implement in existing buildings and result from the simple replacement of existing components.
“The quickest and most inexpensive retrofit a building owner can do is to simply replace toggle switches with wall-switch occupancy sensors,” says Ben Hahn, marketing-product manager with Sensor Switch.
Pete Horton, vice president of market development with Watt Stopper/Legrand, recommends installing sensors with manual-on and automatic-off capability. “These (switches) have demonstrated 20-30 percent savings over standard automatic-on/off sensors and 43-60 percent energy savings over scheduling systems,” he says.
In private offices with bi-level switching, managers might consider replacing toggle switches with relays controlled by a manual-on/automatic-off sensor or auto-on to 50 percent/auto-off occupancy sensor for significant savings.
If a space demands the installation of an occupancy sensor anywhere but on the wall, managers can consider wireless sensors, which run on batteries or ambient light via an integral solar cell. These peel-and-stick devices need no wiring and install anywhere within range of the receiver switch, which replaces the wall switch.
“Wireless sensors offer the most cost-effective way to upgrade existing buildings to be more lighting efficient,” says Bob Freshman, marketing manager with Leviton Lighting Management Systems. “No wires need to be run, eliminating almost all of the labor costs involved in installing hardwired products in existing structures.”
Eddie Hickerson, staff marketing specialist with Schneider Electric, says retrofitting existing lighting panels with intelligent lighting-control-panel interiors is as easy as upgrading occupancy sensors and can deliver solid savings.
“Upgrading existing panel boards with intelligent control has virtually no impact on building operations and typically achieves faster payback periods and greater energy savings,” he says. “It also enables lighting controls to be used to manage peak demand and provide a demand response when requested by the local utility or system operator.”
If an existing building already contains an energy-management system (EMS), the EMS might provide comprehensive HVAC control but no advanced lighting control features. In such cases, managers might consider a lighting-control system designed based on the existing EMS’s protocol, such as BACnet or LonWorks.