Calculate your solar panel size

1. Calculate Your Daily Energy Consumption (kWh)

• Look at your electricity bill to find your average daily energy usage, measured in kilowatt-hours (kWh).
• Alternatively, add up the power ratings (in watts) of each appliance you use, multiply by hours of daily use, and sum them.

Example: If your monthly usage is 600 kWh, divide by 30 to get a daily usage of 20 kWh.

2. Estimate Peak Sunlight Hours in Your Location

• Solar panels generate power only when the sun is shining, and the amount varies by location and season.
• Use an online map or local resources to find the average peak sunlight hours per day for your area.

3. Determine Your Solar Array Size

• Use the formula:
  Array Size (kW) = Daily Energy Consumption (kWh) / Peak Sunlight Hours
  
• This gives you the total wattage required from your solar array.

Example: For 20 kWh of daily usage in an area with 5 peak sunlight hours:

Array Size=20/ 5=4 kW.

4. Adjust for System Losses

• Real-world losses (e.g., shading, dust, inverter efficiency) typically add around 20%.
• Multiply your array size by 1.2 to account for these losses.

Example: Adjusted array size = 4 kW × 1.2 = 4.8 kW.

5. Calculate the Number of Solar Panels

• Divide your adjusted array size by the wattage of each panel.

Example: For 4.8 kW (4,800 W) array size and 400 W panels:

Number of Panels= 4800 W / 400 per panel = 12 panels

Summary Formula

Putting it all together:

Number of Panels= (Daily Energy (kWh)×1.2) / (Peak Sunlight Hours×Panel Wattage)

By following these steps, you can size a solar panel array tailored to your energy needs and local conditions.