Z-Wave is a very efficient, low-energy technology. While your smart home hub will need to be plugged in to keep the network up and running, many Z-Wave deices work on battery power alone, often for a year or more before needing new batteries. Other devices can plug into the wall or behind it, and there are even Z-Wave controllable AC outlets, which let you make your entire home's electrical system "smart" and energy-efficient by controlling and optionally monitoring energy usage. For example, the Qubino Flush 1 Relay PLUS Z-Wave relay module uses 0.4W.