Building value proposition for interactive lighting systems in the workplace: Combining energy and occupant perspectives

Abstract Today, new lighting technologies are rapidly changing energy savings goals and the ways in which those savings are identified and captured. As occupant expectations concerning indoor comfort and well-being are transforming lighting design and engineering solutions, research concerning systems that afford more interaction between occupants, overhead lighting, and local (task) lighting is prudent. This study builds a value proposition by determining risk-based energy savings potential of interactive lighting system while evaluating programmatic success through the measurement of occupants’ psychosocial variables. Post-retrofit data supplied by an overhead lighting control system were combined with empirical energy consumption data from individual tunable desk lamps for a probabilistic return on investment (ROI) analysis. Descriptive and correlational analyses were done to link employees’ environmental perceptions with energy consumption. Even for a modestly energy efficient office building that underwent a lighting retrofit in 2011, it is possible to recover the cost of an interactive lighting investment in nine years. Probabilistically, the rebate appears to be the most important factor in increasing ROI. Occupants perceived overall improvement to the lighting environment after desk lamps had been installed, and that a ‘blending’ had been achieved between task and overhead lighting. The paper proposes a generalizable mixed-methodology to evaluate potential savings. Interactive lighting systems are representative of future building systems that require more human interaction and are prone to irregular operational loads. This research may help facility managers find practical solutions based on existing and emerging technologies to leverage readily available data to aid decision-making processes.