Power

Power is the rate at which energy is transferred or converted. It is measured in watts, written as W, and often appears as kilowatts, written as kW, in home energy documents. In a home energy system, power can describe a live electrical load, an inverter output limit, a battery charge or discharge limit, an EV chargepoint rating, solar output at that moment or heat-pump electrical input and heat output. It is different from energy in kWh: power describes a rate or limit at a moment, while energy depends on how long that power level continues. A 1 kW load running for one hour uses 1 kWh before losses or measurement differences.