Sensors can reduce the lighting energy use of infrequently used spaces by more than 50%. Places like bathrooms, pantries, and storage areas do not need constant lighting and automatic devices can save a lot of energy. Infrequently used stairways and hallways need only minimum safety-oriented lighting and should have occupancy sensors installed to avoid wasting energy when they are unoccupied.
For spaces like hotel guest rooms—or even office spaces where the occupants may be stationary for long periods of time—you may find occupancy sensors counterproductive unless they are properly calibrated.
Picking the right sensors and putting them in the right places is the key to success. For your system to operate properly, each sensor must be able to detect motion at the entrance for non-regularly occupied spaces. Large, open offices usually need multiple sensors to detect movement throughout the space. Consult your lighting system manufacturer for appropriate sensor placement, especially for specialty occupancies.
As each sensor costs $30–$150, develop a lighting layout that strategically combines similar tasks and exposure to daylight to reduce the number of sensors required.
Even if you implemented Strategy 1, daylight sensors within 15 ft of windows, you may be on your way to earning the point for this strategy, but you’re probably not all the way there. You’ll need to put more effort into creating a daylight-responsive space.
Pursue this point if your project space has sufficient available daylight to make a lighting control system that includes daylight sensors worthwhile. Have your lighting designer provide estimated annual energy savings and simple payback calculations and, if warranted, a daylight simulation to examine possible control strategies.
