Solar System Size Calculator
Estimate the solar panel system you need based on your actual appliance usage
// Peak Sun Hours
The average hours per day your location receives strong enough sunlight for panels to produce at rated capacity. Varies by location: 3–4 hrs (UK/northern), 4–5 hrs (mid-latitudes), 5–7 hrs (sunny regions like South Africa, Australia, southern US).
// System Efficiency
Real-world panels don't produce 100% of their rated output. Losses come from heat, wiring, inverter conversion, shading, and panel degradation. 75–85% is typical. Use 80% as a safe default.
// Offset Target
100% means you want solar to cover all your usage. Set higher (e.g. 110–120%) to account for seasonal variation or future usage growth. Set lower if you only want solar to supplement grid power.
// Panel Size
Modern residential panels are typically 370–420W. Each panel is roughly 1.7m² (18 sq ft). Commercial panels can be larger. Adjust the panel wattage to match the panels available from your installer.