What are peak sun hours?
Peak sun hours are not just daylight hours. It is the equivalent number of hours per day when solar irradiance averages 1000 W/m^2.
Calculator
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Analysis
Interpretation of the current calculator output
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How to Use
Step-by-step instructions
- 1Enter your average monthly electricity bill ($).
- 2Enter the average peak sun hours for your location (usually 3-6).
- 3Enter the wattage of the panels you plan to use (e.g., 400W).
- 4The calculator will estimate the system size and panel count.
System Sizing
Estimates required system size based on daily energy usage and local peak sun hours, adding a 25% buffer for system inefficiencies.
Size (kW) = (Daily kWh / Sun Hours) x 1.25Variables:
Daily kWhMonthly Usage / 30Sun HoursAverage peak sun hours per day1.25Efficiency factorExample
$150 Bill
Inputs:
Bill:$150
Sun Hours:4
Panel:400W
Steps:
- 1.Usage = 150 / 0.15 = 1000 kWh/mo
- 2.Daily = 1000 / 30 = 33.3 kWh
- 3.System = (33.3 / 4) * 1.25 = 10.4 kW
- 4.Panels = (10.4 * 1000) / 400 = 26 panels
Result:
26 Panels (10.4 kW)