What Is a Kilowatt-Hour (kWh)? Your Energy Unit Explained

A kilowatt-hour (kWh) is a unit of energy: the amount used by a 1,000-watt appliance running for one hour. Your bill, your solar generation and your battery capacity are all measured in it.

Why kW and kWh are different

Kilowatts (kW) measure power — how fast energy flows. Kilowatt-hours (kWh) measure energy — how much was used. A 7 kW solar array produces kilowatt-hours over the day; a 10 kWh battery stores them.

• 1 kWh ≈ running a 1,000 W heater for an hour
• A typical home uses 20–40 kWh per day
• A 10 kWh battery stores roughly a third of a day’s use