Standby Power Cost Calculator
Devices left on standby draw power around the clock, even when you think they're off. Enter the number of devices, their average standby wattage and your electricity rate to see exactly what phantom load is costing you each year — and how much CO2 it generates.
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Tip: A plug-in energy meter (€10–€25) measures the exact standby draw of any device. Without one, use 3 W as a reasonable average across mixed household electronics.
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Standby Power Inputs
Typical standby wattage by device
Common questions
How much does standby power cost per year? +
A typical home with 10 devices each drawing 3 W on standby for 20 hours per day uses around 219 kWh per year. At €0.28/kWh that costs roughly €61 per year. Homes with more devices or older electronics can see standby costs of €80–€150 per year.
Which devices use the most standby power? +
The worst offenders are typically set-top boxes and cable receivers (5–15 W), older games consoles (1–15 W), desktop PCs in sleep mode (1–10 W) and microwaves with clocks (2–5 W). Modern devices with EU or US Energy Star standby ratings must draw under 0.5 W, but older equipment can draw many times more.
How do I measure standby power? +
Use a plug-in energy meter (also called a power meter or watt meter). They cost €10–€25 and plug between the device and the wall socket. Switch the device to standby and read the watt display. This gives you the exact standby draw rather than an estimate.
Do smart plugs actually save money on standby? +
Yes, for devices drawing more than 1–2 W on standby. A smart plug cutting standby on a set-top box drawing 10 W for 18 hours per day saves around 65 kWh per year — worth €18 at €0.28/kWh. A smart plug costs €10–€20, so payback is under two years per device in that scenario.
What is the difference between standby and off? +
Standby means the device is waiting to receive a signal (remote control, network command or timer) and continues to draw power. Off via a power switch or smart plug means no power draw at all. Many devices labeled "off" are actually in standby — only removing them from the mains eliminates the draw entirely.
Understanding standby power and phantom load
What is standby power and why does it matter?
Standby power — sometimes called phantom load, idle current or vampire power — is the electricity consumed by devices that are plugged in but not actively in use. Virtually every modern electronic device draws some power on standby, from under 0.1 W for a phone charger to over 15 W for an older cable receiver left running overnight.
How much does standby power add to a typical electricity bill?
Studies by the International Energy Agency put standby consumption at 5–10% of household electricity use in most developed countries. In a home using 4,000 kWh per year, that represents 200–400 kWh — equivalent to running a second fridge all year. At €0.28/kWh, that is €56–€112 wasted annually on power that does nothing useful.
The devices worth targeting first
Not all standby draws are equal. A phone charger left plugged in with nothing connected draws under 0.5 W — barely worth removing. A set-top box drawing 12 W for 20 hours a day uses 87.6 kWh per year and costs around €25 at typical European rates. Focus on high-wattage always-on devices first: cable boxes, older games consoles and desktop PCs left in sleep mode.
Measuring standby power accurately
The most accurate way to measure standby draw is a plug-in energy meter. These devices cost €10–€25 and display real-time wattage. Put the device into standby mode and read the display after 30 seconds. This eliminates guesswork and lets you prioritise which devices to put on smart plugs or switched power strips.
Want to understand the full picture of standby costs? Read How Much Does Standby Power Cost?