Solar Panel Calculator

The number of solar panels needed depends on your energy usage, roof space, panel wattage, and sun exposure. Calculate your monthly energy consumption, divide by peak sun hours and panel output, then account for system efficiency.

Solar panel wattage is the amount of energy a panel produces under perfect conditions. Higher wattage panels produce more electricity, so you'll need fewer panels to meet your energy needs, saving roof space and installation costs.

Typically, you need about 100 square feet of roof space per 1kW of solar panels. A standard residential solar panel is about 17.5 square feet, so a 6kW system would need approximately 600 square feet of roof space.

Production ratio is the estimated annual energy output of your solar system divided by its rated capacity. It accounts for factors like weather, shading, and system efficiency. Most residential systems have a production ratio between 1.3-1.6.

While south-facing roofs are ideal for maximum solar production, east and west-facing roofs can also work well. North-facing roofs are generally not recommended as they receive minimal direct sunlight throughout the day.

Peak sun hours represent the average daily solar irradiance in your location. More peak sun hours mean your panels will generate more electricity. This varies by geographic location, with southern regions typically having 5-7 peak sun hours daily.

Most residential solar systems operate at 80-90% efficiency when accounting for inverter losses, wiring losses, and other factors. Higher quality components and proper installation can achieve efficiency rates closer to 85-90%.

While 100% offset is possible, many homeowners choose 80-90% offset for better economics. Consider future energy usage changes, net metering policies, and whether you want backup power capabilities when deciding on system size.