Solar Panel Calculator

The average US home uses about 900 kWh per month and needs 20-25 solar panels (400W each) to offset 100%% of electricity usage. Homes in sunnier regions need fewer panels, and homes in cloudier areas need more. Your actual number depends on your electricity consumption, roof orientation, shading, and panel efficiency.

Each standard solar panel is about 18 square feet (roughly 3.5 x 5.5 feet). A 20-panel system needs about 360 square feet of usable roof space. South-facing roof sections with minimal shading are ideal. East and west-facing roofs work too but produce about 15-20%% less energy than south-facing.