Retrofitting to existing infrastructures, MeshScape 6424 Wi-Stat II wirelessly integrates multiple sensors and control actuators to optimize energy consumption and comfort within each zone in commercial and industrial HVAC environments. It utilizes 802.15.4 unlicensed radio band and operates bidirectionally within wireless sensor network for intelligent control action. Connecting to existing HVAC wires for power, system replaces existing analog, digital, and/or pneumatic thermostat.