How many solar panels do I need?

Panels = Daily kWh / (peak sun hours × panel wattage × efficiency). Average US home needs 20-25 panels (400W each).

What size solar system for a house?

Average US home uses ~30 kWh/day. With 5 peak sun hours and 80% efficiency: 30/(5×0.8) = 7.5 kW system.

Each panel needs about 1.7-2.0 m². A 25-panel system needs roughly 42-50 m² of roof space.

System size = daily kWh / (peak sun hours × efficiency). Panel count = system size / panel wattage.

Efficiency (~80%) accounts for inverter losses, temperature derating, soiling and wiring losses. Each panel needs ~1.7 m².

Average home: 20-25 panels (400W each).

~7-8 kW for average US home (30 kWh/day).

~42-50 m² for 25 panels.