What is a watt vs a watt-hour?
A watt (W) is a unit of power, while a watt-hour (Wh) is a unit of energy.
Watts = Watt-Hours / Hours
The number of watts is a good measure of how much power your panels will produce in a moment of time. Watt-hours provides a measure of how much energy you’ll use in a provided period of time (hour).
For example, if your energy consumption is 15kWh (1,000Wh = 1kWh) over the period of 5 hours, then your average power demand is 3kW:
Power = 15kW-Hours / 5 Hours = 3kW