Basic electrical theory says that a Watt = Volts (V) x Amps (I). Watts are also sometimes referred to as “power”. Knowing this allows you to correlate the power requirements for different things. The image below shows how many 200 watt solar panels you’d need to run a corresponding number of 100 watt incandescent light bulbs. In very rough terms, if these 5 solar panels collected 5 hours of energy from the sun in a given day (5KWh) you’d logically be able to run 10 100W (.83A @ 120V) incandescent light bulbs for 5 hours as well. Using more efficient equivalent 30W compact fluorescent light (CFL) bulbs could allow you to run 3 times as many light bulbs. The following NREL website provides examples of the power requirements for different household items. Using some of that data, you could extrapolate that these same 5 solar panels capturing 5 hours of sun a day (5KWh) might run your oven on bake for approximately 4 hrs a day or run an energy efficient refrigerator for 55 hours. You wouldn’t need to capture the energy because you’re feeding your power into the power companies’ grid and they give you the credit towards your power bill.
What is a “watt” and how can it help me?