Earlier this month, I posted a new whitepaper at the Lighting Control Association website that talks about the findings of a new study about combining occupancy sensing and bilevel switching.
According to the Advanced Lighting Guidelines, occupancy sensors in private offices can produce up to 45% energy savings.
A 2002 study by ADM Associates found that bilevel switching (multilevel switching with 3-lamp luminaires, the inboard lamp switched separately from the outboard lamps) produces 22% energy savings in private offices.
At least one-half of the energy codes in the United States are based on the International Energy Conservation Code (IECC), which requires automatic shutoff of lighting when it’s not being used, such as via an occupancy sensor, while also requiring light level reduction controls such as multilevel switching or dimming in enclosed spaces such as private offices. But IECC says that if an occupancy sensor is used in an enclosed space such as a private office, light level reduction controls are not needed, suggesting an either/or choice.
What if bilevel switching was combined with occupancy sensor functionality? Would this produce higher energy savings in a private office than bilevel switching or occupancy sensing alone. And: What combination of manual initiative and automation would produce the highest energy savings while also satisfying workers?
The California Lighting Technology Center (CLTC) organized a study in eight private offices at the University of California and found that combining the functionality of occupancy sensing and bilevel switching in a single device (controlling two relays for two zones of lighting) saved more energy than if an auto-ON occupancy sensor was used alone. In fact, using a manual-ON occupancy sensor saved 46% more energy than an occupancy sensor alone, and an auto-ON-to-50%-light-level sensor saved even more–52%.
This kind of research shows how controls can be used to maximize energy savings in private offices without sacrificing lighting quality. It’s likely to influence future energy codes.
Click here to read the article and learn more about the study results.
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