How Many Solar Panels Do I Need For 1500 Kwh Per Month

To determine the number of solar panels required to generate 1500 kWh per month, several factors must be considered:

  1. Peak Sun Hours (PSH): This is the average number of hours per day that sunlight falls on a surface at its maximum intensity. PSH values vary geographically and can be obtained from solar insolation maps or online calculators.
  2. Solar Panel Efficiency: Solar panel efficiency is the percentage of sunlight converted into electricity. Typical solar panel efficiency ranges from 15% to 25%, with higher efficiency panels producing more electricity for the same amount of sunlight.
  3. Solar Panel Wattage: Solar panels are rated in watts, which indicates their electricity-generating capacity. Common residential solar panels range from 250 to 400 watts per panel.
  4. System Losses: Solar energy systems experience losses due to factors like shading, wiring resistance, and inverter efficiency. Typically, system losses are estimated to be around 10-15%.

Formula to Calculate Number of Solar Panels:

Number of Solar Panels = (Monthly Energy Consumption / (Peak Sun Hours x Solar Panel Efficiency x System Losses)) x 1000

Example Calculation:

Assume the following values:

  • Peak Sun Hours (PSH) = 5 hours per day
  • Solar Panel Efficiency = 20%
  • System Losses = 15%
  • Monthly Energy Consumption = 1500 kWh

Plugging these values into the formula:

Number of Solar Panels = (1500 kWh / ((5 hours x 0.20) x (1-0.15))) x 1000

Number of Solar Panels = (1500 kWh / (1 hour x 0.20) x (0.85))) x 1000

Number of Solar Panels = (1500 kWh / 0.17) x 1000

Number of Solar Panels = 8823.53


Based on these assumptions, approximately 9 kilowatts (kW) of solar panels would be required to generate 1500 kWh of electricity per month. This represents around 22 to 36 solar panels, depending on the specific panel wattage chosen.

It’s important to note that these calculations are estimates and actual results may vary depending on specific conditions, such as shading, roof orientation, and weather patterns. Consulting with a qualified solar installer is recommended to determine the precise number of solar panels needed for your specific location and requirements.

Ahmad Ghayad

Ahmad Ghayad is the Creator of, a website created to help people build and understand how solar power systems work. He is a passionate Mechanical Engineer that worked in the building and maintaining several solar power systems for houses and organizations during a severe domestic power outage in his country.

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