Standby power draw
Standby power is what a charger consumes while plugged in but not charging — typically 1–8 W. At 5 W standby, a charger burns about 44 kWh a year doing nothing; the best certified units draw under 1 W.
ENERGY STAR’s EVSE dataset reports measured "no vehicle mode" input power for every certified charger, which is the number shown as standby draw on this site’s spec pages — a genuine differentiator between otherwise similar models.