To calculate the consumption of an electrical appliance in kWh, you have to take into account three factors:
The calculation is as follows:
[number of hours’ use] x [number of days’ use] x ([capacity of appliance expressed in watt] / 1,000) = number of kWh
The capacity should be divided by 1,000 to convert the number of watts into the number of kilowatts. This finally gives us the number of kWh (kilowatt hours).
A radio alarm is on all the time and therefore uses energy continuously.
|hours / day||24 hours|
|days / year||365|
|Capacity of radio alarm||10 watts|
Annual energy consumption of radio alarm: 24 x 365 x (10 watts / 1,000) = 87.6 kWh
In the table below we assume that the vacuum cleaner is used for two hours once a week.
|hours / day||2 hours|
|days / year||52 days|
|Capacity of vacuum cleaner||2000 watts|
Annual energy consumption of vacuum cleaner: 2 x 52 x (2,000 watts / 1,000) = 208 kWh
Take a look at the list giving the consumption of the most common electrical household appliances.
Subscribe to our newsletter and stay informed about energyfacts.