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Comparison of electricity consumption

Price of electricity € / kWh
Averaged use per day h
Averaged use per week h

Device 1 Device 2
Power in W (VA)
30 days
Consumption in kWh
Costs in
Difference in
365 days
Consumption in kWh
Costs in
Difference in
5 years
Consumption in kWh
Kosten in
Difference in

The results are rounded to significant digits.

This is a calculator to compare the consumption of electric energy by two devices with different power. The costs are compared as well.

Usage: Type the price of electricity, the power of the two devices in watt as well as the daily or weekly time of operation into the corresponding fields. After a mouseclick on any free space of the window or on the "calculate" button the calculation is performed. Read the result for the duration of a month, a year and of five years.
Move the mouse over a unit or click on it to read its full name. For another calculation just change the input values or you may click the "reset" button, eventually.
Other costs as for the purcase of the devices and the electricity network are not considered.

Example: You want to exchange a conventional bulb with a power of 75 watt by an energy saving bulb with a power of 14 W. As mean daily operation time you estimate 3 hours (5 hours in winter and 1 hour in summer). You pay 16 ¢ per kilowatt hour.
Type the values into the corresponding fields. When you use "0.16" for the price the result will be displayed in €. After a mouseclick on any free space of the window or on the "calculate" button you can read the result. Within a year (365 days) the costs for the electricity used by the conventional bulb of 82.125 kWh are 13.14 €, With the energy saving bulb you have to pay 2.45 € for 15.33 kWh. Therefore, you save 5.913 €. After 5 years you would have saved 53.44 €.

- Large and small numbers are written exponentially. As example 2.3e5 = 2.3⋅105 = 230000 or 4.5e-5 = 4.5⋅10-5 = 0.000045.
- There is no warranty for the conversion. Cactus2000 is not responsible for damage of any kind caused by wrong results.
- Please send an email if you have suggestions or if you would like to see more conversions to be included.

© Bernd Krüger, 27.03.2009

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