A 10kW solar system typically requires 25–34 panels, depending on panel wattage. Key factors include solar irradiance, panel efficiency (18%–22% for monocrystalline), and daily sun. . Example: For a 10 kW solar system, you can use 33 300-watt PV panels (9900 watts) + 1 100-watt solar panel to bring the total up to 10,000 watts or 10kW solar system. We see 16 300-watt panels on this side of the house (4,800W), and there are 16 300-Watt PV panels on. . Location Impact is Massive: The same home using 1,000 kWh monthly could need just 16 panels in sunny Arizona but 22 panels in Massachusetts due to solar production ratios varying from 1. Future-Proofing Saves Money: Adding panels later costs significantly more due. . The answer depends on several factors, including the wattage of the solar panels you choose and the average sunlight your location receives. Average Wattage of Solar Panels: Most residential solar panels have a wattage rating between 250 to 400 watts.