Planting a tree can make a big contribution toward more comfortable living, according to U.S. Forest Service meteorologists. Serving as a wind barrier, the tree (especially an evergreen) can reduce wind velocity in winter and heat loss from the home. A modest investment in an evergreen windbreak planting will give the homeowner many decades of increasingly important fuel savings, they say.
The location of the windbreak is the key to its effectiveness. Most cold winds throughout the nation come from the north or the west. Therefore, windbreaks should be located on those sides, with an extension on the eastern side wherever space permits.
The south side should be left open to permit the sun to enter. The sun lies low in the southern sky in winter, but an open southern exposure permits the yard and house to absorb the heat.
The maximum wind reduction appears at a distance of from four to six times the height of the windbreak, so plantings should be established at that distance from the house.
During the summer properly placed shade trees are remarkably efficient in cooling houses and other buildings with the exception of the very tall ones, the meteorologists say. It can reduce or eliminate the need for costly energy-consuming air conditioning.
Deciduous shade trees come into leaf in late spring, when the daily temperature begins to climb. All summer long they absorb the sun's heat, and at the same time transpire cooling water vapor. In the fall when the temperature drops, the leaves shed automatically, and the sun can shine on house or office walls, adding its heat to that produced by the furnace.
Properly-shaded homes have little need for air conditioning. Even when air condidtioners are installed, they need to work only half as much to do their job in a shaded house as compared to one on which the sun beats down unimpeded on walls and roof.
Differences of 8 degrees have been recorded between shaded and unshaded outdoor surfaces. In addition to trees, deciduous vines are effective in cooling walls in summer.
For masonry walls, clinging species are good cooling devices. The leaf blades intercept and absorb the rays of sunlight while behind them a convection current carries the warm air up and away from the wall.
Clinging vines are not good for wooden walls because their stems and tentrils hold moisture and cause the wood to deteriorate.However, the same cooling effect can be achieved by training twining vines on trellises.