The key to saving energy is to DEFLECT solar power, not capture it. We already have special solar deflecting paint for rooftops which reflects a good deal of sunlight therefore preventing solar heat from being absorbed by homes. The greatest part of electric bills during much of the year is to power air conditioners so less absorption of solar heat means less energy needed to cool down homes. Why the use of solar deflecting treatment of rooftops is not more widespread, I don’t know.
We have a huge window in our living room that faces west. We have never really used the living room before so never really noticed it except that it was always a little warmer in there. I recently put a new sofa and a big tv in there and started using the room. Wow! When sitting on the sofa in the afternoon you can feel the heat coming in the window behind you. Am currently looking for solar screens to fit that window.
It was widely in use in the south prior to the advent of widespread residential air conditioning. White shingle roofs, white gravel roofs and silver metal roofs were quite common. They're not so common anymore. Dimensional architectural shingles in stylish colors, most not very light in color, are the norm now.
Didn’t one of Obama’s EPA guys suggest painting all rooftops and roads white?