If you have been interested in going solar, kW and kWh have most likely come up a few times. If you are confused by this, don’t worry. It’s easy to get kilowatt (kW) and kilowatt-hours (kWh) mixed up when talking about energy consumption. The main difference between kWh and kW is in what they measure. To put it simply, a kilowatt is a measure of power and a kilowatt-hour is a measure of energy; power is the rate at which something uses energy, and energy is the capacity to do work.