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Electricity cost of devices
What do the TV, the games console or a device on standby cost per year? Enter power, running time and your electricity price. And if an efficient device is to replace the old one: after how many years the purchase pays for itself through the electricity bill.
The power is on the rating plate or the power supply; a plug-in energy meter measures it more exactly. Standby: the standby power and the hours the device just waits, often 20 or more.
The unit price from your electricity bill, in cents per kilowatt hour. 35 is only an example. You pay the standing charge anyway, it does not belong here.
For the new device the yearly consumption is on the energy label. For the old one, measure it for a week with an energy meter and multiply by 52. Fridges in particular do not run all the time, so watts times 24 hours would be far too high.
Only electricity is counted. Whether a swap is worth it also depends on how long the old device would still last, and making a device costs energy too. If the electricity price rises, it pays off sooner.
Related: Meter readings and consumption (German) · Subscriptions and fixed costs · Convert units
The calculation runs only on your device. Nothing is stored.
How it works
- 01Enter the power in watts and the hours per day, plus on how many days of the week the device runs.
- 02Take your electricity price in cents per kWh from your bill.
- 03Cost per year, month and day appear at once. Under “Old vs new” you compare two devices.
The formula. Consumption per year in kWh = watts × hours per day × days per week × 52.14 ÷ 1,000. A year has 365 ÷ 7 = 52.14 weeks. Cost = kWh × price in cents ÷ 100.
Example 1: TV. 100 W, 4 hours every day, 35 ct/kWh: 100 × 4 × 365 ÷ 1,000 = 146 kWh per year, that is €51.10 per year or €4.26 per month.
Example 2: standby. A device waiting at 5 W for 20 hours a day: 36.5 kWh per year, at 35 ct that is €12.78 per year for nothing.
Example 3: new fridge. The old one uses 300 kWh per year, the new one 150 kWh according to its label. At 35 ct you save €52.50 per year. If the new one costs €600, it has paid for itself after a little over 11 years.