kilowatt

Everyday

1. (science) A unit of power equal to 1,000 watts, written kW. tree →
2. It measures how fast an electrical machine uses or makes energy. tree →

In the lessons

In science and maths lessons pupils convert units (1 kW = 1,000 W) and work out energy use; electricity bills charge for kilowatt-hours (kWh): using 1 kilowatt for 1 hour. Kettles, heaters and car engines are rated in kilowatts. Phrases: kilowatt-hour (kWh), a 2-kilowatt heater.

Examples

• A kilowatt is 1,000 watts. tree →
• Our kettle uses 3 kilowatts of power. tree →
• Electricity is sold in kilowatt-hours. tree →
• The solar panels on our roof make about 4 kilowatts on a sunny day. tree →
• 2.5 kilowatts is the same as 2,500 watts. tree →
• The electric car's motor is rated at 150 kilowatts. tree →
• A 1-kilowatt heater on for 3 hours uses 3 kilowatt-hours. tree →

Note

Countable. Symbol: kW (small k, capital W). Trap: a kilowatt (kW) is power (how fast); a kilowatt-hour (kWh) is energy (how much). In maths problems: multiply kW by hours to get kWh; multiply by 1,000 to get watts.