US Patent 9857091 Thermostat circuitry to control power usage

An operation alteration of a network attached thermostat to control power usage. Control wires for a heating and air conditioning system may be connected to a thermostat control circuit configured to control the system. A power extraction circuit may be coupled to the control wires configured to extract power from the control wires. The power may be put into a storage device. The power may be provided to the thermostat control circuit and a WiFi radio module. The radio module may provide a network connection for the thermostat. Circuitry and techniques may be provided to reduce power usage by the thermostat components.