Ivy of the wall

We often see ivy on the wall of the old house. What do you think about it? Ivy of the wall is taking an important part in ecology, actually.

Leaves absorb energy in summer (reduction of the energy of the wall to the room). And leaves wither in winter (enough necessary energy). Therefore, ivy of the wall resolves the problem of the most difficult and basic element(cool in summer,warm in winter) in building houses.