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 WiFi Temperature Humidity Monitoring Switch Advanced remote control via iOS/Android apps
Smart WiFi Thermostat Temperature Controller WiFi Smart Control for remote adjustment