With the adoption of new state and local energy standards aimed at reducing global energy consumption, virtually every non-residential building will be facing more stringent lighting control requirements. Whether these standards are based upon ASHRAE Standard 90.1, the International Energy Conservation Code (IECC), or a particular state-developed provision, meeting the requirements with a flexible, easy-to-use, and economical lighting control system may seem impossible. Nevertheless, through the aid of advancing technology a lighting control system can be achieved that eliminates energy waste, while creating a cost-effective and user-friendly environment.
With few exceptions, both ASHRAE 90.1 and the IECC state that the general interior lighting in any building (greater than 5,000 square feet) shall have automatic shutoff control. This ensures that the lighting will be turned off when it is no longer needed. In the past, energy standards allowed manual lighting controls. However, manual controls are most often the reason that large amounts of lighting energy are wasted, due to the fact that the decision to shut off the lights lies solely in the hands of the user. In fact, studies have shown that replacing manual lighting controls with automatic shutoff devices can reduce energy consumption by as much as 50 percent. For instance, depending on the upcoming increase in energy costs for a particular region, a 100,000 square foot office building equipped with automatic lighting controls has the potential to save up to $40,000 a year in energy costs.
“…studies have shown that replacing manual lighting controls with automatic shutoff devices can reduce energy consumption by as much as 50 percent.”
Consequently, the lighting industry has developed a variety of automatic shutoff devices to facilitate this transition. One option available to consumers is the occupancy sensor. An occupancy sensor automatically turns off the lighting in a space when it detects the absence of people, making it most effective in spaces where people frequently move in and out of the space in unpredictable patterns, such as private offices. There are different types of sensing technology and mounting configurations available depending on the application.
Another option for automatic control is the elapsed-time switch, which is a wall device that allows the occupant to turn the lighting on in a space for a preset period of time. The lighting then goes off at the end of the time interval, unless the cycle is restarted by the occupant or manually turned off sooner. Elapsed-time switches are an easy and economical approach to complying with the energy standards in spaces such as utility rooms that are visited infrequently.
The most expensive, yet most flexible, option for automatic lighting control is the centralized lighting control system (CLC). A CLC system consists of at least one intelligent lighting control panel and one or more timed-override switches located throughout the building. The CLC system can be programmed to turn the lighting on or off throughout the day in response to a user-programmed time schedule. In addition, occupants have the ability to override the shutdown in their space by pressing a local timed-override switch. The CLC system panels can also be used in conjunction with occupancy sensors, making the system even more flexible and user-friendly.
Automatic shutoff devices will not only provide building users with the means to reduce their energy bills and comply with governing energy standards, but more importantly, they will ensure that everyone takes the opportunity to make a difference in saving our global environment without ever having to lift a finger.
– Jennifer L. Harrington, PE, LC, LEED AP