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Tariffs and changing tariff

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What is a kilowatt-hour (kWh)?

A kilowatt-hour (kWh) is a measure of how much energy you’re using.

For example, you use 1 kWh of electricity to keep a:

  • 1,000-watt microwave running for 1 hour
  • 100-watt light bulb on for 10 hours
  • 40-watt light bulb on for 25 hours

When you give us an electricity meter reading, you're telling us how many kilowatt-hours of electricity you've used since your last reading.

Your gas meter actually tells you how much gas you've used in cubic meters or cubic feet. But we convert this into kWh to keep things simple.