UnitsUp to date · Jan 15, 2026

Watt (W)

A unit of power equal to one joule per second. Solar panels are rated in watts (W) or kilowatts (kW = 1,000W).

Related Terms

kWh (Kilowatt-hour)

A unit of energy equal to 1,000 watts used for one hour. This is how utilities measure your electricity usage.