What are peak sun hours?

Peak sun hours are not the total hours of daylight but the equivalent hours of full 1000 W/m² solar irradiance. A city receiving 5 peak sun hours receives the same total solar energy as 5 hours of peak noon sun.

What is system efficiency?

System efficiency (typically 75-85%) accounts for inverter losses, wiring losses, soiling, shading, and temperature effects. A 400W panel in a 80%-efficient system produces 320W net output per peak hour.

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Solar Panel Calculator

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Solar Panel Output Calculator

Peak Sun Hours by City

Panel Wattage (W)

Number of Panels

Peak Sun Hours / Day

System Efficiency (%)

Electricity Rate ($/kWh)

System Cost ($, optional)

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Estimate solar output, savings, payback, and CO2 offset. Ten city peak sun presets. Inputs: panel watts, count, sun hours, efficiency, electricity rate, system cost.

How to Use

1Click a city preset to auto-fill peak sun hours, or enter your own value
2Enter panel wattage, number of panels, and system efficiency
3Enter your electricity rate ($/kWh) for savings calculations
4Optionally enter system cost for payback period calculation
5Click Calculate to see daily/monthly/annual production, savings, payback period, and CO₂ offset

Features

Daily/monthly/annual kWh production
Monthly and annual savings ($)
Payback period (system cost ÷ annual savings)
Annual CO₂ offset (0.386 kg/kWh)
10 city peak sun hour presets
System efficiency adjustment
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Solar Panel Calculator

Solar Panel Output Calculator

How to Use

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Frequently Asked Questions

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