The 24/7 rule
One watt running continuously uses 8.76 kWh per year. At the 2026-05 U.S. residential average of 18.44 cents per kWh, that is about $1.62 per year. Ten continuous watts cost about $16.15 per year. Your actual annual cost depends on the prices charged across the year.
Measure before buying controls
Modern electronics can have very low standby draw, while network equipment, set-top boxes, older audio systems, and devices with heaters may use more. A plug-in meter reveals whether a smart plug or power strip can save enough to matter.
Do not switch off essential loads
Refrigerators, medical devices, security systems, network equipment needed for alarms, sump pumps, and equipment requiring safe shutdown should not be disconnected casually.
- Group entertainment equipment that can shut down together.
- Use built-in sleep settings before adding hardware.
- Focus on measured continuous loads, not the number of plugs.
Put the result in context
A 5-watt standby load costs far less than a 1,500-watt heater running several hours per day. Prioritize high-power or long-runtime equipment before chasing tiny loads.
Sources and further reading
DOE: Estimating appliance energy useCalculations are estimates. Utility bills, appliance measurements, and manufacturer documentation take priority over generic examples.