PVWatts Calculator
Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and
The power rating of solar panels is in “Watts” or “Wattage,” which is the unit used to measure power production. These days, the latest and best solar panels for residential properties produce between 250 and 400 Watts of electricity.
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.
A 400W panel in California (5.5 sun hours/day) produces roughly 2,200Wh daily, enough to power a fridge (700Wh) and LED lights (100Wh) with energy to spare. Use the PVWatts Calculator (NREL tool) for precise local estimates. Use the local peak sun hours to estimate daily output accurately.
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.☀️
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