Most residential solar panels have a power output of around 250-400 watts, and can produce up to 2. 5 kilowatt-hours of electricity per day. Why don't those numbers add up? Because a solar panel only produces energy when the sun is out, so we can't multiply 400 by 24 to determine its. How much solar power can you generate based on your roof size? In a perfect world, the average roof in the U. But also, the world isn't perfect. 5% output per year, and often last 25–30 years or more. Average installations for homes can vary substantially, often between 3 kW to 10 kW, 4. A single panel in a solar system will produce about 2 kWh per day, but there are many variables that impact the generation of solar. The answer depends on various factors, including where you live, the size and orientation of your roof, and the efficiency of the solar panels.