It is 30 degrees outside today and the wind is blowing 25 miles per hour. Now would be a good time to consider redoing the landscaping, particularly looking for plants to conserve energy in and around the house.
Planting trees and shrubs around buildings will help reduce heating and cooling costs. How much it reduces the cost depends on the homeowner’s choice of plants and where they are located. Trees and shrubs can also reduce noise and air pollution and make a home more attractive and valuable. Therefore, money spent on landscaping is a good investment.
Trees and shrubs planted around the foundation create a “dead air” space that slows the escape of heat from the building. Such plantings also help reduce air infiltration losses around the foundation of the house. Evergreen trees and shrubs are thicker and more effective than deciduous plants. To be most effective, the evergreens should be planted close together to form a tight barrier against air movement.
Another thing to consider in reducing energy cost is the wind. Unprotected homes lose much more heat on cold windy days than on equally cold, still days. Well-located trees and shrubs especially on the north side of the house can intercept the wind and cut heat loss.
Infiltration or air leakage accounts for as much as one-third of heating loss in some buildings. Cold outside air flows through cracks around windows, doors, and even through pores in the walls. Both windbreaks and foundation plantings can reduce this penetrating power of the wind.
If room permits, windbreaks should be two to five rows of trees and shrubs. Evergreen trees and shrubs make the best protection, especially if they are planted on the north side of the house.
A shaded home has two-thirds less heat flowing into it from shaded walls vs. sunlight walls. Unshaded roof temperatures often exceed 140 degrees. Light colored roofs help, but not as much as well-placed trees.
Properly located deciduous shade trees are one of the most efficient sun control devices. Shade can reduce summer heat on the south windows by 20-25 percent; south walls by 30-35 per-cent; east and west windows and walls by 50 percent.
The homeowner should choose large shade trees for east and west shade and plant them 10 to 20 feet from the house, in parallel lines if more than one tree is planted. Where maximum winter sun is desired, choose open branch trees like pecan, bur oak, Chinese pistache and sycamore.
Oaks and other tall trees with full crown are best for summer shading. Their high branches permit greater visibility and do not block the flow of cooling summer breezes.
Evergreens and Shumard oaks have cone-shaped crowns which provide less shade on roofs and walls. Their branches often extend to the ground, blocking visibility and flow of cooling breezes. If placed in the wrong location, they may shield the house from the sun’s warmth in the winter.
Choose open branched trees for the south side of the house where conserving energy in both summer and winter is about of equal concern. Any trees taller than 20 feet will hasten winter sunlight from 25 to 95 percent depending on the tree.
Trees provide maximum shade when planted in groups beside the house. However, a roof need not be totally shaded to achieve excellent results so long as 20 percent or more of the roof is shaded for the entire day.
Homeowners who want to develop their own landscaping plan can get more information from various sources. Those homeowners who lack the basic knowledge of landscaping, should consider hiring a landscape architect. The cost is minimal and could save a homeowner in the long run.
A last note, increasing insulation and sealing windows and doors will go a long way in stopping cold or warm wind from entering the house.
Jim Coe lives in Lawton.