Lesson 3
kW, kWh and Your Meter
Tell power from energy, see what your meter and in-home display actually count, and read the right register safely.
Builds on
Speed and distance
An in-home display shows two kinds of number, and they mean different things. One is in kilowatts (kW): how fast your home is using energy right now. The other is in kilowatt-hours (kWh): how much energy has been used in total. kW is your speed; kWh is the distance on the clock. Bills call each kWh a unit.
One kWh is what a 1 kW load uses in an hour. A 2 kW heater left on for half an hour uses 2 × 0.5 = 1 kWh. Your meter is the odometer: it counts kWh, and that distance is what you pay for.
Turning kWh into pounds, with unit rates and standing charges, is covered in Checking an Energy Bill.
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