Green Technology

... "On a clear day around noon, incident solar radiation is approximately 100 Watts/square foot (1,000 W/square meter). Mono-crystalline (single crystal) and multi-crystalline solar panels change about 15-18% of the incident sunlight into electricity. Therefore it takes roughly 70 to 60 square feet of roof area respectively for a 1 kW solar electric system. Thin film technologies such as amorphous silicon panels are approximately 8% efficient and a 1 kW array would take up twice the area of a crystalline array. " ...