Landscaping To Conserve Energy
Proper Landscaping
Printable PDF version (4 pages)
Too frequently people do not use landscape plants to conserve energy. Proper placement of trees, shrubs, and vines around a house conserves energy while adding beauty. Trees are the number-one landscape plant used in energy conservation in the home landscape.
Trees help remove pollutants from the atmosphere that can damage humans. They also can absorb carbon dioxide and other gases while producing oxygen for us to breathe. Trees and other plants reduce the greenhouse effect by shading houses and office buildings. This benefit reduces air conditioning needs up to 30 percent because less electricity is required for cooling. Properly placed trees within the landscape can be as effective as other home improvements in reducing heating and cooling costs. Good selection and placement of trees within the landscape can help cool your house in summer and allow sun's rays to warm your house in winter.
Trees can add to the value of property, as well. Well-landscaped property is more desirable than property that is not landscaped, so healthy trees and other plants can increase residential property values up to 15 percent.
To install properly an energy conserving landscape, you must understand the different positions of the sun at various times of the year. Figure 1 shows the movement of the sun in mid-December (winter solstice). Notice that the sun rises in the southeast and remains low in the sky during the day. The winter sun sets in the southwest. Figure 2 shows the position of the sun on June 22 (summer solstice). The sun rises in the northeast and appears higher overhead at midday. The sun sets in the northwest during summer.
Place trees around
the house to provide shade from hot morning and afternoon sun. Trees on
eastern and northeastern exposures of the house provide morning shade
in summer. Trees placed on western and northwestern exposures of the house
provide shade during afternoons, as shown in Figure
3. Increase the effectiveness of reduced heat absorption by having
a shrub or a vine shade east and west walls. You can grow vines on masonry
brick or concrete walls, but do not allow them to grow directly on walls
with wood sidings. Provide a simple trellis for wooden sidings.
Effective tree placement
will allow the winter sun to warm the roof and walls of your house. As
you can see in Figures 1 and 2,
the southern exposure is intense in Mississippi. The most important factor
to consider in placing trees on the south side of your house is the use
of deciduous tree species. Deciduous trees lose their leaves in winter
and allow the sun to warm houses. Avoid using evergreen
trees such as pine, American holly, magnolia, and cedar on the south side
of your house. These trees remain green all year, shading the house from
the warm winter sun. Houses on properties with a heavy cover of pine trees
result in winter shade. Provide winter sun by removing pines that are
too close to your house. You can use deciduous trees to provide needed
shade for summer.
In most areas of Mississippi,
winter winds prevail from the north and from the northwest. Proper tree
placement reduces the effect of winter winds on a house. A screen planting
of evergreen trees along the north and northwest areas of your property
will provide wind protection. Figure 4
shows how the planting controls air flow. Notice that the protected
or void area is approximately two times as deep as the height of the trees.
The "thumb rule" for placing the trees is to make the protected or void
area twice as deep as the trees are tall. Remember, newly planted landscape
trees and shrubs will grow in maturity to greater heights. Be sure you
place them according to their expected mature sizes.
In most areas of Mississippi,
prevailing summer winds are provided by the Gulf breeze from the southwest
and from the south. To take advantage of cool summer breezes, avoid dense
screen plantings on the southwest and south sides of your property. Prune
deciduous trees on the southern exposure of your house to the height of
the roof's drip line to provide free air movement into the house.
Mississippi
State University does not discriminate on the basis of race, color,
religion, national origin, sex, sexual orientation or group affiliation, age, disability, or veteran status. Copyright
by Mississippi State University. All rights reserved. (POD February 2005)
Planning
for Summer Shade
Planning
for Winter Sun
Placing
Trees for Wind Protection
Planning
for Cool Summer Breezes
Tips for Placing
Trees for Energy Conservation
For More
Information
The Mississippi State
University Extension Service can provide you with more information upon
request. Call your county Extension office and ask for relevant publications.
Original manuscript
by Jim Perry, landscape architect
Revised by David Tatum, Ph.D., state nursery specialist, and Norman
Winter, Ph.D., horticulture specialist, Dpeartment of Plant and Soil Sciences.
Extension Service of Mississippi State University, cooperating with U.S.
Department of Agriculture. Published in furtherance of Acts of Congress,
May 8 and June 30, 1914. Joe H. McGilberry, Director
This document may be copied and distributed for nonprofit educational purposes
provided that credit is given to the Mississippi State University Extension
Service.
