The size of your solar array is determined by the amount of power you need and the size of your roof’s footprint. As a general rule, each solar panel will produce between 250 to 300 W. If you have 10 panels, you’ll typically make between 2,500 and 3,000 W or 1 kW.

A typical array has 5 kW (each kW is worth 1,000 W). If your roof has a smaller footprint or more shade issues, your installer might recommend a higher efficiency panel to maximize the limited space.

Your production capacity is reported in kilowatt-hours (kWh). You’ll see this figure on your current electricity bill. Because Arizona, Texas, and similar areas have a lot of sunshine, they are great spots for producing electricity.