tado thermostat: Depleted battery symbol
The batteries are depleted and need to be replaced. Changes on the device itself are blocked until they are.
Applies to: tado° Smart Thermostat and Wireless Temperature Sensor. What you see: a symbol.
What to do
tado° Help Center gives no step for this on the page cited; the meaning above is all it says.
Source
tado’s own help page, read on the date shown.
- tado° Help Center: What do the symbols on the Smart Thermostat or Wireless Temperature Sensor user interface mean? — tado° Smart Thermostat and Wireless Temperature Sensor (V3+ and earlier). support.tado.com Checked 2026-09-29.
A similar symbol on other thermostats
The same symbol on another maker’s thermostat can mean something else.