A device uses 1 kilowatt (kW) of power for 1 hour. How much energy does it consume?
1 kilowatt hour (kWh)
Energy consumed equals power multiplied by time: E = P x t.
Here P = 1 kW and t = 1 hour, so E = 1 kW x 1 h = 1 kilowatt hour (kWh), the commercial unit of electrical energy.
1 watt hour is 1000 times smaller, 1 joule is far too small (1 kWh = 3.6 x 106 J), and kilowatt is a unit of power, not energy.
Hence, the answer is 1 kilowatt hour (kWh).
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