Solar attic fans are pretty

[afx114]

Solar attic fans are pretty cool:

http://www.acoolerhouse.com/solar-attic-fans.html

Good article: http://www.signonsandiego.com/uniontrib/20070722/news_1hs22dulley.html

What is nice about these is, on the sunniest days when the most ventilation is needed, these fans, powered by the sun, run very fast. On cool, cloudy days, less electricity is produced and they run slower.