Planting Trees for Energy Efficiency

Posted on Nov 20, 2009

When it comes to comfort and efficiency, the beauty of trees is matched by their utility. Strategically planted trees around your home create a beautiful landscape while also providing energy savings all year round. Deciduous trees that shed leaves in the autumn can provide shade to cool a home in the summer, while allowing sunlight and its warmth into the interior of the home in the winter. Well placed conifers and other evergreen trees and shrubs can deflect or block winter’s harshest winds.

Cooling

Trees can shade a roof and walls from the hot summer sun. They will also create a cooler atmosphere around the home, cooling sidewalks and driveway that normally reflect heat. They are able to do this through a transpiration process that cools the air around them, acting as natures evaporative coolers. According to one study, cooling costs can be cut by 50 percent if half of the roof is shaded. Shading the air conditioner will also improve its efficiency by 10 percent.

When planting trees and shrubs around your home:

• Consider the seasonal sun angles when planting for sun shade. Buildings with large south or west exposures need shad mid to late afternoon.
• Medium to large trees provide excellent cooling because they shade both home and yard, helping to cool both the structure and the surrounding areas.
• Plant deciduous trees to the southeast and southwest of the home for shade. Choose and place trees to cast the maximum amount of summer shade and the minimum of winter shade. Make sure the trees are placed far enough away from the house as to not interfere with the structure as the tree matures.
• Shrubs and small trees can be planted to shade air conditioners and heat pumps. However, be careful not to plant too close to the unit as to block airflow. Keep units free of leaves and needles.

Heating

Properly placed trees and shrubs can help reduce heating costs by blocking winter winds. Deciduous trees planted to cool a home, will loose their leaves to allow the radiation of the sun to help heat the structure.

Conserve energy by planting a combination of evergreen trees and shrubs on the side of your home that blocks the coldest of winter winds. Choose plants whose branches will grow low to the ground.