Trees can save you energy dollars. You might think, “That is a nice thought but can trees actually save me energy dollars?” The simple answer is “Yes.” Not only can your trees save you energy dollars, they can also add value and beauty to the investment of your home. Let us dig a little deeper into this energy saving tree strategy.
In the United States, 22% of our energy usage comes from our homes. We gain or lose heat in three basic ways. http://content.ces.ncsu.edu/conserving-energy-with-plants
Air infiltration – passage of air through cracks and around doors or through open windows and doors. The average home loses 20-30% of heat in winter by air infiltration;
Heat conduction – conduction of heat through materials of which the house is built. Controlling the temperature difference and air movement between inner and outer surfaces of walls, floors and ceilings is the best opportunity for reducing heat conduction. Heat conduction represents up to 50% or more of the total heat exchange between a home and the outside environment;
Solar radiation – heat is transmitted into homes by penetration of the sun’s rays. Up to 90% will be transmitted into the living area if rays are received perpendicular to a single pane.
According to the USDA Forest Service, trees around your home can reduce your air conditioning needs by 30%. The U.S. Department of Energy say properly placed trees can save you $100 to $250 a year.
An energy-conserving landscape utilizes trees, shrubs, groundcovers, and vines to provide cooling summer shade as well as insulation against heat loss in winter. It also serves aesthetic purposes. A windbreak, for example, can define the space in a yard or patio and provide privacy while blocking blustery winds. And by using plants as living air conditioners or insulating blankets, you can soften a house’s architectural edges with foliage and flowers while improving its performance.
A study done by Purdue University found one 15-foot-wide silver maple in good health can add $2562 to the value of your home. http://energysavingtrees.arborday.org/#About
What Trees Save You Energy Dollars?
In Minnesota, we live in what is called a “cool” ciliate.
Deciduous trees, those that lose their leaves in the fall work well for shading. Shade from trees reduces air conditioning needs and makes non-air conditioned homes more comfortable. Plant deciduous trees so they will shade east-facing walls and windows from 7 to 11 a.m. and west-facing surfaces from 3 to 7 p.m. during June, July, and August. Trees with mature heights of at least 25 feet should be planted 10 to 20 feet east and west of the house. Plant smaller deciduous or evergreen trees with lower limbs northwest and northeast of the building to provide late afternoon and early morning shade. Trees planted to the southeast or southwest should be about four times their mature height from the building.
Large and small evergreen trees and shrubs save energy by slowing north cold winds in the winter. Effective windbreak trees have crowns that extend to the ground and branches that keep their foliage in winter (evergreens). Junipers, spruces, firs, Douglas-fir, and evergreen shrubs are good choices for wind protection.
Trees should also be planted to shade paved areas. Light energy striking dark pavement like asphalt is absorbed, causing the air above to be heated. Light colored pavement absorbs less energy, but can reflect it toward a building. Tree leaves reduce heat and reflection as they absorb light energy and use it to evaporate water.
Air conditioners should also be shaded from mid-morning through evening. Prune branches to allow at least several feet clearance around the air conditioning equipment to encourage air flow. Shrubs should not be planted near the air conditioner or they will reduce airflow and cooling efficiency.
Both deciduous and evergreen trees save energy in summer by directly cooling the air. This cooling happens as water evaporates from the leaf surfaces, much as our skin is cooled when we perspire.
Tips for Planting Energy Saving Trees
The temptation is to plant the fastest growing species available. However, this is usually a poor choice for several reasons. Trees that grow at rates that are more moderate usually live longer, are less likely to break in wind and ice storms, and are often more resistant to insects and diseases.
Avoid creating future problems when planting trees. Remember that a four foot tall, two-foot wide tree might end up being 60 feet tall and 30 feet across. Learn the mature size and crown characteristics of any tree you buy and plant accordingly.
Always check for underground utility lines before digging for your trees.
Check with your local County Extension office or local nursery for more details on the best trees for your home situation.
Trees do not ask for much — dirt, water, sunlight. Yet they provide a wealth of benefits: They improve the air you breathe, cut your energy bills, provide a home to wildlife, and they add beauty and value to your home, they beautify your neighborhood, reduced urban heat island effect, and a smaller carbon footprint, just to name a few.
My thanks to the following sources for this information on Using Trees for Energy Saving