Solar Panel Calculator | Lowe''s
Once you''ve determined the right kind of solar panels for your home, look at your latest electric bill. This will help you determine your average annual energy usage, which will
About 97% of home solar panels installed in 2025 produce between 400 and 460 watts, based on thousands of quotes from the EnergySage Marketplace. But wattage alone doesn't tell the whole story. In fact, efficiency matters more than wattage when comparing solar panels—a higher wattage can simply mean that a panel is larger.
This solar panel wattage calculator allows you to calculate the recommended solar panel wattage according to the energy consumption of your household appliances. If you want to know more about solar panel sizes and wattage calculations, feel free to explore our fun and helpful solar panel calculator.☀️
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.
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. In simpler terms, a panel's wattage rating tells you its maximum power output under ideal conditions.
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