How Much Energy Does A Solar Panel Produce?
Most residential panels in 2025 are rated 250–550 watts, with 400-watt models becoming the new standard. A 400-watt panel can generate roughly 1.6–2.5 kWh of energy
For example: A 100-watt panel can produce 100 watts per hour in direct sunlight. A 400-watt panel can generate 400 watts per hour under the same conditions. This doesn't mean they'll produce that amount all day, output varies with weather, shade, and panel orientation.
About 97% of home solar panels included in EnergySage quotes today have power output ratings between 400 and 460 watts. The most frequently quoted panels are around 450 watts, so we'll use this as an example.
A 400-watt panel can generate roughly 1.6–2.5 kWh of energy per day, depending on local sunlight. To cover the average U.S. household's 900 kWh/month consumption, you typically need 12–18 panels. Output depends on sun hours, roof direction, panel technology, shading, temperature and age.
Let's demystify it. What Does Solar Panel Wattage Mean? Wattage refers to the amount of electrical power a solar panel can produce under standard test conditions (STC), which simulate a bright sunny day with optimal solar irradiance (1,000 W/m²), a cell temperature of 25°C, and clean panels.
PDF version includes complete article with source references. Suitable for printing and offline reading.
Download detailed product specifications, case studies, and technical data for our off-grid PV containers and mobile energy storage solutions.
15 Innovation Drive
Johannesburg 2196, South Africa
+27 87 702 3126
Monday - Friday: 7:30 AM - 5:30 PM SAST