Commercial buildings represent a significant portion of energy consumption and environmental emissions worldwide. To help mitigate the environmental impact of building operations, building energy management systems and behavior-based campaigns designed to reduce energy consumption are becoming increasingly popular. In this paper, we describe the development of a modular socio-technical energy management system, BizWatts, which combines the two approaches by providing real-time, appliance-level power management and socially contextualized energy consumption feedback. We describe in detail the physical and virtual architecture of the system, which simultaneously engages building occupants and facility managers, as well as the main principles behind the interface design and component functionalities. A discussion about how the data collection capabilities of the system enable insightful commercial building energy efficiency studies and quantitative network analysis is also included. We conclude by commenting on the validation of the system, identifying current system limitations and introducing new research avenues that the development and deployment of BizWatts enables. (C) 2014 Elsevier Ltd. All rights reserved.