Monitoring and control of electromechanical devices from a central data center. The data center may be located at a separate geographic location, using broadband communication channels, such as Internet or telecom channels, and wireless HAN (home area network) communications. Such electromechanical devices may comprise, for example, an HVAC system at a small-business or residential site, a grounds-maintenance sprinkler system, or a small wind or solar energy generation and storage station.