Standby Power Cost Calculator
Estimate the annual cost of standby power drain from devices left plugged in.
Enter standby wattage, number of devices, and your electricity rate.
Standby power (also called vampire power or phantom load) is the electricity a device draws when it is switched off but still plugged in. It is not zero. Most modern electronics maintain standby circuits, keep displays lit, and listen for remote signals around the clock.
The Lawrence Berkeley National Laboratory measured standby power for hundreds of devices. Typical numbers: set-top cable box: 10-20 W, game console: 1-10 W, microwave: 2-3 W, desktop power supply: 2-6 W, phone charger with no phone: 0.1-0.5 W, TV in standby: 0.5-3 W.
The formula
Annual kWh = watts x number_of_devices x 8,760 hours / 1,000
Annual cost = annual kWh x electricity rate
An average U.S. home has standby losses of 50-100 watts continuously. That is 440-880 kWh per year, or $57-$115 at national average rates. The EPA estimates standby power accounts for roughly 5-10% of total residential electricity use in developed countries.
What to do about it
Smart power strips cut power to peripheral devices when the primary device (like a TV or PC) is off. Plug-in timers work well for coffee makers and chargers. Smart outlets let you schedule cuts remotely. For devices that rarely need instant-on response, simply unplugging is the most effective option.
Energy monitors (like Kill-A-Watt) plug between your device and the outlet and measure real wattage. Measuring actual standby draw takes 30 seconds and is far more accurate than manufacturer claims, which often understate real-world consumption.