A kilowatt (kW) is a unit of electric power usage that equals 1,000 watts. (A watt is equal to 1 joule per second.)
While even the most powerful LED grow light is unlikely to reach to wattage of 1 kW, kilowatts are an important measurement for designing the grow lighting system as a whole. The combined wattage of multiple grow lights in a single system adds up quickly. And to understand the demands of your grow light system, you also need to calculate kilowatt hours. Not only do these calculations help you determine your energy costs, but they also allow you to confirm that the utility company can meet the demand of your grow operation.