Thermostat or app reports low battery on an ecobee SmartSensor

Safety: No electrical hazards. Handle coin-cell batteries carefully and keep away from children.

• Step 1 – Open the SmartSensor: Gently pry open the sensor housing according to ecobee’s instructions.
• Step 2 – Replace the battery: Install a new, high-quality coin-cell battery of the specified type (often CR2477 or model-specific). Match the polarity markings.
• Step 3 – Re-seat and test: Close the housing, place the sensor back in its location, and check the ecobee app to confirm the battery status updates.
• Step 4 – Optimize placement: Avoid placing sensors in very cold or very hot locations, which can shorten battery life.