I have been thinking about it for a while. In a hot and dry environment (az, nm, tx) most of the heat is gained by the sun. It is easy to see. If you leave your

I have been thinking about it for a while. In a hot and dry environment (az, nm, tx) most of the heat is gained by the sun. It is easy to see. If you leave your car in the sun, it will be extremely hot. But if you leave your car in the shade of a tree it will be ok. You don't even need the solar cells, all you need is to create a shade for your house. Something that covers the sun, but still allows air to go through. Trees is probably the best option, if you have the space. Other materials could be some sort of ceramic tiles that rest about 10 cms above the ceiling of the house or use a shade cloth. I have tested the shade clothes, they seem to be very thin and they let a lot of light go through, but if you touch the concrete floor underneath it is not too hot as opposed to the place where the shade is not covering the floor.