You can drastically reduce your home heating and cooling costs using this simple passive heating and cooling technique. Plant deciduous trees or vines (on pergolas) along the sides of your house that get full sun, especially near windows. In the summer, the trees and vines will shade the walls and windows, preventing heat build-up inside the house.
At my place, our shady deciduous trees and vines provide us with delicious summer fruits such as plums, figs, almonds, pears, apples, pomegranates and grapes.
In the winter, the bare trees allow the sunshine to heat your home, if you leave the curtains and shutters open during the day (but make sure to close them at night, to keep the heat inside). This technique is known as passive solar heating. The sunshine will also make it light and bright inside, reducing the need to switch on the lights during the day. To collect extra heat in winter, place dark coloured heavy items (ceramic pots, pot plants) inside the windows, in direct sunlight. They will absorb the heat and release it later in the day. If you are renovating, consider using dark coloured floor tiles, stone or concrete near the windows to act as heat sinks. These passive solar design techniques will save you money and reduce home energy costs both in summer and winter.