LANDSCAPING FOR ENERGY CONSERVATION

LANDSCAPING FOR ENERGY CONSERVATION
William C. Welch
Extension Landscape Horticulturist
Texas Agricultural Extension Service
Although it is not possible to control temperature, wind and other weather elements, certain landscape practices can modify the climate in and around homes significantly. By placing trees, shrubs, vines and landscape structures properly, the homeowner can reduce the energy required to keep homes and surrounding areas comfortable during winter and summer. If the landscaping is well done, one receives the added benefits of beauty and increased real estate values. A well planned landscape is one of the best investments a homeowner can make. Protection From the Sun Trees. Trees can reduce summer temperatures significantly. Shading the roof of a house from the afternoon sun by large trees can reduce temperatures inside the home by as much as 8 to 10 degrees F. Deciduous trees (those that lose their leaves in winter) provide summer shade, then drop their leaves in the fall, which allows the warmth of the sun to filter through their bare branches in winter and help warm the home. If a home can be situated to take advantage of shade from existing trees on south and west exposures, energy expended to cool the house can be reduced considerable.
To shade the roof or a wall of a one-story home, trees which will reach a medium to large size should be selected and placed 15 to 20 feet from the side or 12 to 15 feet from the corner of the structure. To be most effective, the canopy of the tree should extend over the roof. Smaller trees such as crape myrtles and redbuds can be planted closer to the house and used for shading walls and window areas. Since they are deciduous, they will provide shade during the summer and allow light and sun to penetrate during the winter season.

Another way to reduce energy consumption with trees and shrubs is to provide shade for the outside portion of a split system air conditioner. A study by the American Refrigeration Institute shows that shading of this type can reduce the temperature inside the home as much as 3 degrees F. However, shrubs planted near the compressor should not obstruct the air flow or access for needed service. In addition to reducing energy consumption, screening outdoor air conditioning equipment with plantings enhances the esthetic value of the home.
Espaliers and Vines. In addition to shading roof areas, plants can protect walls from heat and cold. Vines, shrubs and certain trees can be used as espaliers (plants trained to grow flat against walls). The foliage cover insulates the wall against summer heat and cold winter winds. Trees, shrubs and vines can be highly effective in reducing noise and dust pollution also.
There are several ways to support plants against walls. Some vines such as English Ivy have specialized roots that cling to masonry or wooden surfaces. However, this can harm wooden surfaces since it hastens the decomposition of the wood and provides protection for termites and other insects. Vines that do not cling usually twine and must have support. This can be provided by trellises placed on or close to the house. A third way to support shrubs and vines on a wall is to place mortar nails in the joints between the brick and tie plant stems securely with plant ties or similar material.
Windows as well as walls may be shaded by vines on trellises. Deciduous vines such as Boston Ivy and wisteria will allow the sun to penetrate during the winter. If a quick effect is desired, annual vines such as morning glories and moon vines can be planted economically from seed in early spring and usually will provide the needed shade in time for the hottest summer weather.
Overhead Structures. Arbors and slatted wooden overhead structures can be effective either attached or adjacent to the home or farther out in the landscape. If adjacent to the home, they provide the bonus of shading walls and windows, thus reducing heat and glare and providing cool, restful sitting and viewing areas.
If wooden structures are used, the 1 or 2 inch strips of treated pine, redwood, cedar or other long-lasting wood are usually spaced 1 to 1 1/2 inches apart. This spacing provides adequate shade while allowing the air to circulate freely. If vines are used as a partial or complete cover, the structure is referred to as an arbor. Grape arbors, once as common as patios are today, can serve as attractive, practical additions to the landscape. Muscadines are excellent for arbors since they require little or no spraying for insects and disease problems and are attractive plants which produce tasty fruit. Wisteria, Carolina jessamine and grapes are other popular choices which are well adapted to most of the state.
Groundcovers. The temperature a few inches above turf or other groundcover plants is frequently 12 degrees to 15 degrees F. lower than above asphalt or concrete surfaces. By using turf and groundcover plants between homes and paved areas such as drives and walks, summer temperatures can be reduced. Consult your county Extension agent or local nurseryman for recommendations on adapted groundcovers and turf species in your area. Protection From the Wind
Although living windbreaks have been utilized for many years, their value has increased with the advent of higher fuel costs. Winter winds in Texas usually blow from the north or northwest and accelerate the rate of air exchange between a house and the outdoor environment. Savings up to 23 percent have been recorded in comparing completely exposed homes and a house landscaped to minimize air infiltration.
Summer winds normally blow from the south or southwest with generally positive effects on human comfort. Tall trees from the south and west can reduce the temperature while allowing breeze to pass beneath and through the foliage canopy.
Planning Windbreaks. Windbreaks obstruct and redirect the flow of wind. AS wind strikes an obstruction it can move over, around or through it. The extent of protection on the leeward side is related to the height and length of the windbreak. Impenetrable windbreaks create a strong vacuum on the protected or leeward side which reduces the protection. Windbreaks composed of living plants allow some of the wind to penetrate which makes them more effective. The effective zone of protection for a living windbreak is approximately thirty times its height although maximum protection occurs in a range of 5 to 7 times the height of the planting. Therefore, if planning a windbreak 25 feet tall, it should be located 125 to 175 feet (5 to 7 times 25 feet) from the house to be most effective.
The following criteria are helpful in planning an effective windbreak:
1.The optimum foliage density for the windward side is about 60 percent.
2.Windbreaks are most effective when they extend to the ground.
3.The width of the planting is important as it relates to penetrability. For most evergreen plants, two or three rows are sufficient but if deciduous materials are being used, four or five rows may be necessary. Rows should be staggered.
4.Windbreaks work most efficiently when the length is 11.5 times greater than the mature width.
5.The height of species within the width of the windbreak should be varied to create rough windbreak edges.

Selecting Species for Windbreaks. Some of the species appropriatefor windbreak plantings in various parts of Texas are:

Upper Panhandle of Texas Oriental Arborvitae (Thuja orientalis) Eastern Red Cedar (Juniperus virginiana) Austrian Pine (Pinus nigra) Ponderosa Pine (Pinus ponderosa) Scotch Pine (Pinus sylvestris) Russian Olive (Elaeagnus angustifolia) North and West Texas Eastern Red Cedar (Juniperus virginiana) Rocky Mountain Juniper (Juniperus scopulorum) Aleppo Pine (Pinus halepensis) Oriental Arborvitae (Thuja orientalis) Arizona Cypress (Cupressus glabra) Russian Olive (Elaeagnus angustifolia)

Central and South Texas Arizona Cypress (Cupressus glabra) Elaeagnus (Elaeagnus pungens) Salt Cedar (Tamarix aphylla) Japanese or Tree Ligustrum (Ligustrum lucidum) Eastern Red Cedar (Juniperus virginiana) Rocky Mountain Juniper (Juniperus scopulorum) Yaupon (Ilex vomitoria) Oriental Arborvitae (Thuja orientalis)

Other Types of Windbreaks.
Still another way to moderate the temperature inside the home is to use rows of shrubs on the northwest side to protect it from cold winter winds as well as to direct summer breezes around it.
Good landscaping practices offer one of the most practical methods of reducing energy consumption in homes. When the homeowner considers the added benefits of increased real estate value and more attractive homes and communities, the investment becomes an even greater bargain.

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This material has been prepared for distribution in cooperation with the Department fo Energy and the Governor's Office of Energy Resources in support of the Texas Energy Conservation Program (Agriculture). Educational programs conducted by the Texas Agricultural Extension Service serve people of all ages regardless of socio-economic level, race, color, sex, religion or national orgin.
Cooperative Extension Work in Agriculture and Home Economics, The Texas A&M University System and the United States Department of Agriculture cooperating. Distributed in furtherance of the Acts of Congress of May 8, 1914, as amended and June 30,1914.

Fall, late winter and early spring are ideal planting times since adequate moisture and cool weather can promote root growth before hot dry weather. Mulching the newly set out plants helps prevent excess moisture loss and heat gain. For additional information on transplanting and fertilizing woody plants, ask county Extension agents for Fact Sheets L 1037 How to Transplant Wood Plans and L-1097 Fertilizing Woody Ornamentals. In addition to traditional windbreaks, shrubs can also be used closer to the home for winter protection. This is more practical for small areas and subdivision lots where space does not allow the use of conventional windbreaks. For this type of protection, dense evergreen plants are most appropriate. They should be planted close enough to form a solid wall and far enough away from the house (about 4 to 5 feet minimum) to create a dead air space. This relatively still or dead air has much less cooling power than moving air which can decrease the loss of heat through the walls.

Saving Energy and Energy Conservation and Implementation

Saving Energy and Energy Conservation and Implementation

Some of the energy we can use is called renewable energy. These include solar, wind, geothermal and hydro. These types of energy are constantly being renewed or restored.

But many of the other forms of energy we use in our homes and cars are not being replenished. Fossil fuels took millions of years to create. They cannot be made over night.

And there are finite or limited amounts of these non-renewable energy sources. That means they cannot be renewed or replenished. Once they are gone they cannot be used again. So, we must all do our part in saving as much energy as we can.

In your home, you can save energy by turning off appliances, TVs and radios that are not being used, watched or listened to.

You can turn off lights when no one is in the room.

By putting insulation in walls and attics, we can reduce the amount of energy it takes to heat or cool our homes.

Insulating a home is like putting on a sweater or jacket when we're cold...instead of turning up the heat.

The outer layers trap the heat inside, keeping it nice and warm.

New space-age materials are being developed that insulate even better. This person's fingers are protected by Aerogel Insulation Material created by the Lawrence Berkeley National Laboratory. The person cannot even feel the flame!

Recycling

To make all of our newspapers, aluminum cans, plastic bottles and other goods takes lots of energy.

Recycling these items -- grinding them up and reusing the material again -- uses less energy than it takes to make them from brand new, raw material.
So, we must all recycle as much as we can.
We can also save energy in our cars and trucks.
Make sure the tires are properly inflated.
A car that is tuned up, has clean air and oil filters, and is running right will use less gasoline.
Don't over-load a car. For every extra 100 pounds, you cut your mileage by one mile per gallon.
When your parents buy a new car, tell them to compare the fuel efficiency of different models and buy a car that gets higher miles per gallon.
You can also save energy in your work place or school.
Each week you can choose an energy monitor who will make sure energy is being used properly.
The energy monitor will turn off the lights during recess and after class.
You can make "Turn It Off" signs for hanging above the light switches to remind yourself.

WHAT ARE THE USES OF ENERGY?

Energy is defined as "the ability to do work." In this sense, examples of work include moving something,

lifting something, warming something, or lighting something. The following is an example of the

transformation of different types of energy into heat and power.

Oil burns to make heat -->

Heat boils water -->

Water turns to steam -->

Steam pressure turns a turbine -->

Turbine turns an electric generator -->

Generator produces electricity -->

Electricity powers light bulbs -->

Light bulbs give off light and heat

It is difficult to imagine spending an entire day without using energy. We use energy to light our cities and homes, to power machinery in factories, cook our food, play music, and operate televisions. In a home where electricity supplies all of the energy requirements, the average energy consumption is shown below:

Air conditioner and heater = 50%

Water heater = 20%

Lighting and small appliances = 10%

Refrigerator = 8%

Other = 5%

Ovens and stoves = 4%

Clothes dryer = 3%

Electricity is generated from both renewable and nonrenewable energy sources. These sources are defined below.

Renewable energy sources:

These sources are constantly renewed or restored and include wind (wind power), water (hydropower), sun (solar), vegetation (biomass), and internal heat of the earth (geothermal). About 9.0 percent of electricity in the U.S. is generated from renewable sources.

Nonrenewable energy sources:

These are natural resources that cannot be replenished (fossil fuels such as oil, gas, and coal). About 71.5 percent of electricity in the U.S. is generated from nonrenewable sources.

In addition to renewable and nonrenewable energy sources, about 19.5 percent of electric power in the U.S. is generated by nuclear power plants. However, operating such plants poses significant nuclear waste disposal problems; consequently, there are no current plans to build more. Most electricity in the United States is generated by burning nonrenewable fossil fuels and there is a limited amount of these energy sources.

WHY IS ENERGY CONSERVATION IMPORTANT?

Because of the limited amount of nonrenewable energy sources on Earth, it is important to conserve our current supply or to use renewable sources so that our natural resources will be available for future generations.

Energy conservation is also important because consumption of nonrenewable sources impacts the environment. Specifically, our use of fossil fuels contributes to air and water pollution. For example, carbon dioxide is produced when oil, coal, and gas combust in power stations, heating systems, and car engines.

Carbon dioxide in the atmosphere acts as a transparent blanket, that contributes to the global warming of the earth, or "greenhouse effect." It is possible that this warming trend could significantly alter our weather. Possible impacts include a threat to human health, environmental impacts such as rising sea levels that can damage coastal areas, and major changes in vegetation growth patterns that could cause some plant and animal species to become extinct.

Sulfur dioxide is also emitted into the air when coal is burned. The sulfur dioxide reacts with water and oxygen in the clouds to form precipitation known as "acid rain." Acid rain can kill fish and trees and damage limestone buildings and statues.

You can help solve these global problems. In the U.S., the average family's energy use generates over 11,200 pounds of air pollutants each year. Therefore, every unit (or kilowatt) of electricity conserved reduces the environmental impact of energy use.

HOW YOU CAN Reduce Energy consumption – THIS WILL HELP YOU?

The following four concepts can help you evaluate your household energy use and identify ways to conserve energy. These concepts will significantly reduce a family utility bill and other energy costs over 1 year.

Changing What You Use

U Walk, ride a bicycle, or use mass transit instead of driving; automobile emissions account for about 60 percent of air pollution in our cities.

U Install compact fluorescent light bulbs that use less energy and last 10 times longer than

incandescent light bulbs.

U Air-dry your clothes on a laundry line instead of using a clothes dryer.

U Install a programmable thermostat that automatically adjusts the temperature when you are in bed or away.

U Buy energy-efficient appliances. There are standard energy use tags attached to most new

appliances that can help you determine which appliance will be the most efficient. These

appliances may be more costly, but your utility bill savings will quickly make up for the extra cost.

Changing What You Do

U Set the thermostat to 68 °F in winter when you're home and down to 55° F when you go to bed or are away (programmable thermostats can do this automatically).

U Insulate the ceiling, walls, and floor of your home.

U Plant a tree next to a window for shade to reduce the need for air conditioning.

U Recycle items such as newspaper, aluminum cans, and plastic bottles; recycling these items

requires less energy than producing them from brand new, raw materials.

U Wash clothes in cold water and only in full loads.

U Use energy-saving settings on washing machines, dishwashers, and clothes dryers.

Improving Your Housekeeping

U Turn down the water heater thermostat to 120° F.

U Turn off lights when leaving a room.

U Close heating vents and close doors to unused rooms.

U Close drapes and windows during sunny summer days and after sunset in cooler weather.

U Stop air leaks around windows and doors with caulk or weather stripping. Air leaks can rob your house of heat in the winter or make it too humid in the summer. As much as 40 percent of your heating and cooling costs can be due to air leaks.

U Clean or change air filters on your air heating system in the winter and on air conditioning units in the summer so that they work more efficiently.

Educating Yourself and Others

U evaluate energy efficiency in your house. (See DOE Website)

U Share knowledge and ideas with family, friends, and neighbors.

WHY IS ENERGY CONSERVATION IMPORTANT?

Energy conservation helps endure resources for the future and also helps prevent pollution.

U know that if we continue to consume nonrenewable sources at an increasing rate, these sources

will be depleted.

U know that not only are we depleting our nonrenewable sources, but that use of fossil fuels has

negative environmental impacts, such as global warming and acid rain.

TESTING THE THEORY OF ENERGY CONSERVATION IS IMPORTANT?

Materials Needed: Two thermometers, two plastic bags (one large and one small), and twist ties

Activity:

U Lay one thermometer inside the small bag.

U Inflate the bag by blowing into it, then close the end with the twist tie.

U Put the inflated bag inside the larger plastic bag.

U Inflate the large bag with air and close the end with the twist tie.

U Place the bag in direct sunlight, and lay the second thermometer next to the bag.

U Observe the temperature reading of both thermometers after 30 minutes.

U Explain to the public that the temperature reading inside the bag should be higher because the

double layer of air inside the bag acts as a greenhouse, just like the atmosphere around the earth.

U Explain to the public that both layers of air allow radiant energy from the sun to enter, and this radiation energy is absorbed and trapped when it is reflected back from the earth. As a result, the temperature near the earth increases, as it does in a greenhouse. Similarly, in this demonstration, when sunlight enters the outer bag (or the earth's atmosphere), the inner bag (or gases in the atmosphere such as carbon dioxide) absorbs and reradiates the heat back toward the

thermometer (or earth), thereby raising the temperature. This situation represents global warming.

U Emphasize to the public that as more gases are released into the atmosphere through the use

of fossil fuels, the more heat is absorbed and trapped in our atmosphere.