Considering a mid latitude (e.g. in Virginia), south facing, single family house with two stories, AC cooling and solar power on the roof:
What would be the ideal level / amount of shade for the house in summer?
An additional condition is that the entire house is shaded, so the question is not about which part of the house should be shaded, but to which degree the entire house should be shaded.
As a concrete example, there's a tree in front of the house. Is it better to cut the tree down or not?
The interior of the house is cooled by an AC unit that consumes electricity. Solar cells on the roof produce electricity from sunlight, which partially offsets the electricity consumption of the AC unit. However, direct sunlight is also heating the house, increasing the power consumption of the AC unit again.
Additional shade shields the house from the heat of the sun, but also may reduce the power from the solar panels.
So the question would be if there is an optimum point there. Shade could come from trees in front of the house, other buildings, or e.g. solar sails.
The answer could also be "None", or "as much shade as possible".