Most previous research in sustainable HCI has focused on electricity consumption in domestic environments or private office spaces. Here, we address use of lighting in public areas of office buildings with the goal of understanding and measuring how calm technologies can inspire positive engagement by promoting awareness and competition. We have conducted a 15-month study with the design, deployment, and assessment of two complementary ambient apparatus (one centralized, one distributed) in an office building occupied by ICT start-up companies. Our results show that calm technology can be effective under specific conditions, resulting in a significant reduction of average electricity consumption. We also discovered that in the absence of automatic controls, approximately 25% of lighting consumption occurred during off-work hours.