#1 Shelterbelts Surrounding the House Properly positioning trees shrubs and perennials around the house is cheapest, most effective method of achieving energy efficiency in the home. The plants and trees not only help keep the house warm in the winter by blocking the northwest wind, but help keep it cool in the summer by blocking the hot summer sun.
The most important rule of thumb to follow is never plant evergreen trees (including spruce, pine, fir and cedar) on the south or east side of the house. While evergreens in these locations are effective in shading the building against the blistering July sun, they also prevent the solar radiation in the winter from doing its part to mitigate heating costs. In fact the shade produced by a mature spruce tree growing on the south side of the house can increase the homeowner’s heating bill to the tune of $250 or more per year.
Instead of using evergreens to grace the southern exposures leaf trees or vines should be used. The leaves provide a barrier to the incoming solar radiation in the summer, while in the winter, the bare branches allow the sun’s rays to reach the home unabated. The other advantage of using trees and vines extensively around the house is that they provide a seamless transition from the house to the landscape.