For all those of you living in a house, with roof and fence, the problem of cooling your residence in the summer is pretty pressing. Solatube has thought at this niche and built a standalone cooling system, Solarstar, based on the Universe-aged principle of cooling by evaporation of water, getting the hot air out, and putting the colder one in.
The principle is so simple, you could do it yourself (you don’t even have to make use of those solar panels, if they’re too expensive, because cooling the attic will save you more than your air conditioner. For being green though, solar panels are more than ok (if you can afford them easily).
So, all you have to do is mount their $300 fan on your rooftop and it will do the rest by itself, because it is powered by a 10W solar panel. The device does this (the pictures are self-speaking, no need for words). Just watch the gallery.