No C Wire Options
Compare no-C-wire smart thermostats by power method: included adapters and extenders, battery power, and the line-voltage systems to rule out.
MoesHouse ZHT S03 Smart Thermostat (Battery Powered, Weekly Programmable)
Smart Thermostat Radiator Valve
Smart WiFi Temperature Humidity Monitoring Switch Advanced remote control via iOS/Android apps
Sinilink SA10/SA10-W Remote WiFi control
Tuya WT20R Remote control via app
Thermostatic Radiator Valve with LCD Display Zigbee 3.0 technology for smart home integration