Energy savings from partially shading an exterior wall

I live in So Calif (Irvine) and this recent heat wave has me looking for practical ways to reduce my AC energy usage. We only use the AC when outside gets above 85F and set the thermostat to 78. House is 2 story 2000 sqft with 4 ton AC unit.

I have a SW facing stucco wall about 12' wide by 15' high that gets very hot to the touch in these 95F+ degree days. It has one double pane window in the lower corner. If I put a 10' x 12' sunshade in front of it will this lower my AC electricity useage by a significant amount? Enough to cover $200 annual cost of summer install and winter removal?

I know you want a simple yes or no but that's not possible without a lot of details about the construction of the wall, insulation, electricity millage rate, angle of the sun etc.

Moreover, even if you provide the right data the calculations are tedious and beyond what most folks are willing to randomly do. I would also point out that expecting a return on your investment in one year at $200 maybe a bit short sighted. You should consider the savings over the entire life span of the sunshade.

In general any thing you do to reduce the heat gain from the sun (Radiant heating) the better and if there is a logical approach that you are comfortable with cosmetically as well economical just do it.