# What is a kWh?

This is a very common question! Energy is billed in kWh(s) - this represents one unit of electricity. Appliances should always state their rate of energy consumption in W (Watts), but this isn't enough to determine usage over a duration. A kWh is simply the rate if consumption multiplied by the period of use. For example, if a kettle is rated at 1kW (1000 W) and its used continuously for 2 hours, then the total energy consumption can be determined by: