In 2025, standard residential solar panels produce between 390-500 watts of power, with high-efficiency models reaching 500+ watts. However, the actual energy output depends on multiple factors including your location, roof orientation, weather conditions, and system design. A typical 400-watt panel generates 1,500-2,500 kWh annually depending on location, with systems in sunny regions like Arizona producing up to 1,022 kWh per. . Solar panels degrade slowly, losing about 0. 5% output per year, and often last 25–30 years or more. A 400-watt panel can generate roughly 1. In this guide, we'll walk you through realistic production numbers, show you how to calculate output yourself, and explain what actually affects performance in the real world.
