Smart Lock Annual Battery Cost Calculator

Smart-Lock Power, Signal, and Battery Life

Signal decides the protocol

Estimate 2.4 GHz RSSI from router distance plus 9 dB per wall. Above -65 dBm suits direct Wi-Fi; -65 to -75 is marginal; below -75, use a hub or move the access point. More than 6 Wi-Fi locks per access point needs a dedicated SSID.

Battery math

Wi-Fi drains fastest, Z-Wave/Thread slowest. Freezing weather cuts alkaline capacity first; lithium holds up. Treat the low end of the interval as the shopping trigger and keep one spare set per lock.