Understanding solar panel specifications to make informed decisions about your solar investment.
The rated power output in watts indicates how much electricity a panel can produce under standard test conditions. Common residential panels range from 350W to 450W.
Panel efficiency measures the percentage of sunlight converted to electricity. Most residential panels have 17-22% efficiency, with premium models exceeding 22%.
This indicates how much power output decreases for each degree above 25°C (77°F). Lower coefficients (around -0.3%/°C) mean better hot weather performance.
Monocrystalline panels offer the highest efficiency, polycrystalline provides value, and thin-film is best for flexible applications.
Most panels come with 25-year warranties covering power output degradation. Look for linear warranties guaranteeing 80-85% output at year 25.
Standard residential panels measure approximately 65" x 39" with thickness around 1.5-2 inches. Check roof space compatibility before purchasing.