There's another way: Overhangs, awnings and trees
During the long, hot summer, roof overhangs, awnings, shutters and well-placed trees can occasionally provide shade to at least some rooms of a home. The amount of shading achieved depends on the coverage, the orientation of the home, the season and the time of day.
South-facing windows can usually be successfully shaded with a roof overhang. The wider the overhang, the more hours of the day it will provide shade. East- and west-facing windows are harder to address with overhangs because the sun can still intrude in the midmorning and midafternoon. Other options include fixed or retractable awnings and shutters.
If you are planting trees for shade, select species that are suitable for your climate and that will mature to the appropriate size, shape and density for each location. For protection from sun in the west, trees with branches relatively low to the ground will best block the low-angled rays typical of late afternoon. For sun from the south, consider deciduous trees that have high branches and leaves that can shade your roof throughout much of the day in the summertime. For continuous shade, plant dense evergreen trees or tall shrubs.