Strategic plantings can cut your energy bills
By Megan McKoy-Noe, CCC
You've upgraded your appliances, insulation, and lighting to help lower your monthly electric bill. What else can you do? Plenty, if you have a yard with landscaping options. Fall is a good time for planting in North Carolina, and the right combination of plants and trees can unearth hidden energy savings.
The U.S. Department of Energy claims that landscaping with energy efficiency in mind, on average, could save enough energy to recoup your investment in less than eight years. Here are two ways to think about planting for energy savings:
In general, residents in North Carolina and the rest of the Southeast should make the most of shade during warm temperatures, but use trees that will eventually lose leaves (deciduous) to let winter sun shine through.
Shading a home with trees could drop the surrounding air temperature by as much as 9 degrees Fahrenheit. It gets better closer to the ground — since cool air sinks down, the air under trees may be up to 25 degree cooler than the air over the driveway.
Different trees serve unique purposes. To block solar heat on hot days but let the winter sun through in cooler temperatures, use deciduous trees. Evergreen trees and shrubs are ideal to provide continuous shade and also block heavy winds.
If you have an air conditioner, shading the unit can increase its efficiency by as much as 10 percent. Shading takes time. For example, a 6-foot to 8-foot deciduous tree planted near a home will begin shading windows in a year. Depending on the species and the home, the tree will shade the roof in five to 10 years. If this seems slow, remember that slow-growing trees have a number of advantages over faster-growing ones. They tend to live longer, their deeper roots make them more drought resistant, and they have stronger branches. Plant trees far enough away from the home so that when they mature, their root systems do not damage the foundation and branches do not damage the roof.
Don't forget about shrubs and groundcover plants. These short but sturdy shade-givers reduce heat radiation, cooling air before it reaches your home's walls and windows.
Windbreaks cut heating costs
Shrubs and trees create windbreaks and can keep wind chill away from a home. During cooler temperatures a windbreak reduces wind speed nearby, saving your home from higher heating costs.
It is always important to check wind directions at your home for yourself. However, generally in North Carolina, prevailing winds come from the northwest year-round; for most of the central part of the state, prevailing winds come from the southwest from November to mid-August; and on the coast, winter winds tend to come from the north and northwest.
It's best to block wind with a combination of trees and shrubs with low crowns — foliage which grows close to the ground. Evergreens are ideal. For the best protection, plan on leaving between two to five times the mature height of the trees or shrubs between the windbreak and the protected home.