What is a kilowatt and a kilowatt hour?

The easiest way to explain the concepts of kilowatt and kilowatt hour (kilowattimme) is to start by looking at what “power” and “energy” entail.

Power and energy

“Power” refers to the amount of electrical energy that a given device uses or produces at a given moment. Power is measured in watts (W). The more power a device uses, the more energy is required to make it work.

Energy is calculated as “power x time” and measured in watt hours (Wh). If you want to know how much energy is consumed when you use a certain device, simply multiply the power by the amount of time you use it.

Kilowatt and kilowatt hour

A kilowatt means “a thousand watts”. Energy is usually measured in kilowatt hours (kWh), which is another name for “thousand watt hours”. On your electricity bills, you will usually see “kilowatt hours” as the measurement used to show how much electricity you have consumed.

Example calculation

If, for example, you have a dishwasher with a power rating of 1,500 watts, which you use for two hours, this produces a figure of 3,000 watt hours, or 3 kilowatt hours.


How much can a kWh be used for?

Precisely how much use you can make of a kilowatt hour (kWh) does vary. Here we have collected a number of examples of approximately how much a single kilowatt hour (kWh) covers for the normal electrical devices you may have in your home.

Example Wattage Time
Advent candelabra, LED  0,7 W 1,428 h
Filament bulb 40 W 25 h
LED light 1 W 1,000 h
String of lights 10 W 100 h
String of lights 30 W 33 h
Low-energy light 7 W 143 h
Example Wattage Time
Air fryer 1,200-2,250 W 25-50 min
Dishwasher 1,000 W 1 h
Electric mixer 500 W 2 h
Fan (for cooker, including lighting)  200 W 5 h
Freezer, class A++  31 W 32 h 
Coffe maker 1,500 W 40 min 
 Refrigerator, A++  13 W  77 h
Microwave oven (full power)  1,000 W  1 h 
Toaster 1,000 W 1 h 
Cooking range, induction (one zone on)  3,000 W 20 min
Cooking range, induction (max. power, all zones on)  7,350 W 8 min
Cooking range, rapid zone  1,500 W 40 min
Cooking range, frying zone  2,000 W 30 min
Oven 2,300 W 26 min
Electric kettle  2,200W 27 min
Example Wattage Time
Shower 5,000 W 12 min
Shower 1,000 W 60 min
Heated towel rail 30-200 W 5-33 min
Hair dryer 2,200 W 27 min
Curling tongs 55 W 18 h
Electric razor 5 W 184 h
Example Wattage Time
LED/LCD-TV (on) 71 W 14 h
Game console 91 W 11 h
Example Wattage Time
Iron 2,200 W 27 min
Drying cabinet  1,000 W 1 h
Tumble-dryer, class B  2,000 W 30 min
Washing machine (40 degrees)  500-1,000 W 30-60 min
Washing machine (60 degrees)  2,000 W 30 min
Example Wattage Time
Air conditioning (A/C)  1,000 W 1 h
Sauna 6,000 W 10 min
Vacuum cleaner   700 W 1,4 h
Computer (stationary, used for playing games)  100 W 10 h
Electric radiator 1,000 W 1 h
Electric boost for heat pump/geothermal heat  3,000 W 20 min
Underfloor heating (1 m2)  128 W 8 h
Infra-heating 1,800 W 33 min
Charging electric vehicle (10 kW)  10,000 W 6 min
Charging electric vehicle (4 kW)  4,000 W 15 min
Charging laptop 67 W 15 h
Charging smartphone 5 W 200 h
Air heat pump (normal use/use for cooling)  500-1,200 W 50 min-2 h
Engine warmer 670 W 1,5 h
Radio 50 W 20 h
Jacuzzi (3–400 kWh/year)  500 W 2 h
Sewing machine 71 W 14 h
Water heater (electric)  3,000 W 20 min