Another reason to consider a Solar Royal solar attic fan is because without proper ventilation your shingles warranty could be in question. It's not just marketing but large companies like "Owens Corning", one of the largest composite shingle manufacturer in the world has this actually listed as a reason in which not to cover warranty of there product. Here is the link to review: http://goo.gl/gw0rF (highlighted) and Limited Lifetime Warranty
Solar Royal, LLC unveils the next generation in premium solar-powered ventilation/attic fans, running 22-watts and retailing $379.
AUSTIN, TEXAS (July 16, 2012) Solar Royal, LLC announces the launch of its flagship product; the premium solar-powered ventilation/attic fan named the SR1800. Solar Royal is a manufacturer, designer and developer of premium solar attic ventilation solutions, starting with the best-built, feature-packed and lower-priced solar attic fan. The SR1800 was developed “…because of the lack of aesthetics, technological features and value proposition previously available in the marketplace.” said Roy Stocker, President