A windbreak can help you create a greater balance between outdoor and indoor temperatures. A coniferous or evergreen windbreak will work to keep out harsh winter winds while allowing the sun’s rays to reach the home and warm its walls. Another option is to combine low-lying shrubs and strategically placed deciduous trees that work together to allow the sun’s radiant rays to warm the house in the winter while slowing wind velocity closest to your home. In the summer, the deciduous trees will leaf out and bring shade and cooling temperatures to the home.
Before you invest, make a careful assessment of your property and how the wind, sun, and existing landscaping work on the exterior of the house. In winter, observe the pattern and direction of snowdrifts caused by blowing snow and take note of how and where the sun hits your home on a sunny winter day. If you live in a neighborhood where the lots are small, remember that neighboring evergreens, especially on the north or west of your home, may provide you with an established windbreak. Consult a landscape architect or your local county extension service to assist you with planning and placement of trees and shrubs.
If you live in a cold or temperate climate, be sure your plan has tall, dense evergreens located away from the home’s south side because they will block the sun’s heat in the winter. Deciduous or leafy trees are great along the south side because they bring shade during summer but let sun stream into the home once they drop their leaves. Southern sun exposure lowers heating costs in the winter as it warms exterior walls. Warmer walls lessen heat loss through conduction.
Plant a windbreak of evergreen trees along the north and northwest sides of your home for protection against harsh winter winds. The most effective windbreaks incorporate several rows of trees and shrubs of varying heights. Air circulation is also very important for efficient windbreaks, so make sure that the mature plantings are not too dense or they could cause a vacuum effect which leads to a dead zone of cold air around the home.
Plant the trees at a distance of two to five times the mature height of the trees from your home. Winds are reduced by 10 to 20 percent when trees are placed at a distance two-and-a-half times greater than that of the tree height. You can achieve up to 50 percent wind reduction when the windbreak is situated at a distance of five to seven times the tree height. The tree limbs and foliage should extend to the ground and they should be hardy enough to withstand strong winds. Broadleaf evergreens are more vulnerable to wind damage than spruce trees, which are denser.
While even one row of evergreen trees will provide some benefit, plant several back-to-back rows of evergreen trees for maximum protection. A good windbreak should have vertical rather than sloping sides to trap wind rather than snow. To guard against windblown snow drifts and promote air circulation, plant a row of evergreen shrubs on the windward side of your break.
Evergreens are fast-growing trees, but you may need fencing or other manmade barriers in the earlier years of growth to achieve the desired efficiency. A fence with a basket-weave pattern works best; a more solid fence installed behind the first adds yet another layer of protection.
Perimeter Plantings for Insulation
Low-lying evergreen shrubs or hedges planted alongside the north, west, and northwest sides of the home also serve as effective buffers from the wind. When planted about a foot away from the home’s perimeter, these plantings create a pocket of air that functions like natural insulation for your home.
Landscaping is an important part of an energy-efficient home, but not the only one. Everything from the way your home is sited on your property to the number of windows you have on the south side of your house comes into play. And of course it’s essential that your home be properly insulated and that cracks in windows and doors be sealed. Heat exchange, a normal process that occurs as a result of the differential between outdoor and indoor air and temperature, can be offset by paying careful attention to all of these factors.
Credit: Renovate Your World