The Extension Kit enables you to control your hot water. It is also needed to connect the tado° Smart Thermostat to your heating system if there is no room thermostat or if you have a wireless room thermostat. The Extension Kit works then as a wireless receiver for the heating system. Replaces a hot water controlling programmer. Controls heating based on sensor data from the tado Smart Thermostat. Needed as wireless receiver in case you exchange a wireless room thermostat or for heating system setups without a room thermostat. Compatible with the UK standard programmer backplate. Accessory to the tado° Smart Thermostat Starter Kit (V2/V3/V3+). Box contains: tado° Extension Kit, installation accessories.