The solar power needed to run a fan depends on the fan's wattage and the desired operation duration. The average American home uses 900kwh per month or 30kwh/day, which is equal to 25-35 250W solar panels. . Ultra-Efficient USB and Portable Fans: These compact coolers draw 5-15 watts, making them incredibly solar-friendly. An 80W solar panel can run a 48 inch blade ceiling fan, while a 100W solar panel can power a. . The efficiency of a solar panel is a measure of how much sunlight it can convert into energy, which is crucial in determining how many panels are needed to power your fans. In the fourth section, we'll look at the different sizes of solar panels and how they affect energy output.