wattuur

Wattuur, abbreviated Wh, is a unit of energy used in electrical calculations and consumer energy metering. It represents the amount of energy transferred or used when power of one watt is applied for one hour. In SI terms, one watt-hour equals 3600 joules.

Because energy is the product of power and time, watt-hour is defined as E = P × t, with P in watts and t in hours. This makes it convenient for expressing electrical energy consumption over time.

Common usage: electricity bills and household appliance energy labels typically express energy in watt-hours or kilowatt-hours. A kilowatt-hour (kWh) equals 1000 Wh and equals 3.6 megajoules; it is the standard unit for household energy consumption and pricing. For example, a 100-watt lamp running for five hours consumes 0.5 kWh.

Notes: the watt-hour is a practical unit for energy but it is not an SI base unit; the joule is the SI unit of energy. The prefix kilo- multiplies energy units linearly: 1 kWh = 1000 Wh. In practice, battery capacities are often quoted in Wh or in ampere-hours at a given voltage.

Spelling and usage vary by language. In Dutch, wattuur is commonly written as wattuur or watt-uur; in English texts it is watt-hour or Wh.