c627 energy efficient landscapingtional landscaping. using plant materials wisely can help reduce...

Energy EfficientLandscaping

Kansas State UniversityAgricultural Experiment Stationand Cooperative Extension Service

Outdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.

Major Plant Arrangement for Energy Efficiency


Introduction

Recently, an architect was15 houses featured in the 1981in Manhattan, Kansas.

Many of these new homes

asked to reviewParade of Homes

claimed to haveenergy-saving features. The reviewer found that few,if any, were responsive to the energy-conservingpotential of siting, orientation overhangs or externalshading devices, and strategic plantings or func-tional landscaping.

Using plant materials wisely can help reduceyour energy costs. Winter heating bills may bereduced as much as 15 percent while the energyneeded for summer cooling may be cut 50 percentor more. Given rising energy costs, even a 10 per-cent energy saving can be significant to the home-owner.

By selecting and placing plant materials prop-erly, you can create shade, channel cool breezes,block winter winds, and control other factors, suchas glare.

Plants also can play a psychological role. Forexample, you feel cooler in the summer by lookingat blue flowers massed together in a border, and agroup of blue spruces on an open green lawn canmake a hot day seem less oppressive.

Even so simple a consideration as placing yourmailbox in the shade can make bringing in the mailmore pleasant.

ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . 1Considerations Before Planning . . . . . 2Landscaping Guidelines . . . . . . . . . . . 8Conclusion . . . . . . . . . . . . . . . . . . . . . . 12

Bringing in the mail becomes a pleasant chorewhen your mailbox is in a shady place.


ConsiderationsBefore Planting

Radiant HeatThe amount of radiant heat the sun adds to a

building depends on the sun’s position in the skyand on the intensity of sunlight. Clouds, air pollu-tion, and the density and thickness of the atmo-sphere affect intensity and radiation.

In winter, when the sun stands lower in the sky,it must penetrate a wide belt of the atmosphere andit loses some of its intensity; even so, it is still areliable source for solar heating.

Approximately one-fifth of the sun’s rays reachthe earth’s surface directly. Part of these rays arereflected.

The sun’s heat combined with the reflection canbe unpleasant. For example, imagine yourself sit-ting in a metal chair on a south-exposed concretepatio in August with a metal table in front of you.You would be well beyond the human comfort zoneof 69 to 80 degrees Fahrenheit.

If you select and place shade trees properly,however, you can bring temperatures back to withinthe comfort zone, or at least make that patio morecomfortable in the summer.

Effects of Winter WindsWe can also shelter ourselves and property

from a blustery winter wind by careful landscaping.In designing residential landscapes, consider thedirection of the winds in each season, the effectthese winds have on human comfort, and how thesewinds can be controlled by plantings.

Winter winds generally blow from the north-west, the cooler portions of the United States andCanada. They have a chilling effect on the perceivedair temperature. For example, a 10-mile-per-hournorthwesterly wind will make an air temperature of44 degrees Fahrenheit feel like 32 degrees Fahren-heit.

Winds accelerate the rate of air exchange be-tween a house’s exterior and interior environments,which results in an increased demand for heatingfuel.

An experiment reports a difference in fuel useof 23 percent between a house that was landscapedto minimize the air infiltration and an identicalhouse exposed to the winter wind. At times of highsnowfall, winter winds accelerate snowdrifting, and

Deciduous trees lose their leaves in the winter, allowing the sun’s rays to enter and heat the house.

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The sun’s position differs in summer and winter.

unprotected broadleaf evergreen plants may bedesiccated by direct exposure to winter winds.

Windbreaks should be designed to interceptand redirect the winter winds before they reach thehouse, outdoor work or play areas, sensitive plants,and roads and driveways.

During winter, functional home landscapingwould capture the sun’s rays and block northerlywinds. By selecting and placing evergreen treesproperly a homeowner can help control winterwinds.

Effects of Summer WindsSummer winds in Kansas generally blow from

the south. Although they may gust occasionally tohigh speeds, they are more moderate in velocitythan winter winds, and their effects on human com-fort are positive. For example, when relative hu-midity is in the 70 percent range, a nine-mile-per-hour wind can make an actual air temperature of

85 degrees Fahrenheit feel more like the high70s—back into the range of human comfort (69 to80 degrees Fahrenheit and 30 to 70 percent relativehumidity). Most people enjoy those summer breezesthrough the house, and using them efficientlyreduces the need for air conditioning. It is generallybest to channel them through the living areas.

Heat Exchange in HousesTo take full advantage of the effects of land-

scape vegetation you need to understand the wayshouses gain or lose heat. Heat exchange occursthrough air infiltration, heat conduction, and radia-tion transmission through windows.

Air infiltration is the movement of outside airinto the home through cracks around doors and win-dows, porous materials, open doors and windows,and other openings.

There is a pressure difference between insideand outside caused either by the force of the windon the outside of the home or by temperature dif-ferences between inside and outside air.

The surfaces that face the wind will experienceincreased air pressures as wind velocity increases,and air will enter through openings in these sur-faces. The incoming air will force an equal amountof interior air out through openings in the surfacesfacing away from the wind. A properly placed wind-break will control this infiltration.

Because warm air rises, temperature differ-ences between inside and outside also will create anatural circulation of air in the home. Warm interiorair will rise and flow out through openings near or atthe top of the house while outside air is drawnthrough the lower openings. This type of circulationhas been referred to as the “chimney effect.”

Direct and reflected radiation is reduced greatly with the use of plant material.

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Air infiltration created by temperature differ-ences and that caused by the wind often occur at thesame time. The chimney effect is more important inwinter because of the large temperature differentialbetween interior air and the outside air. The combi-nation of high winds and temperature difference cancause a high air infiltration rate.

The result may be a complete air change withina house as often as several times an hour. In winter,heat losses from air infiltration may represent up tohalf the total losses. For the average home duringnormal winter conditions, from 20 to 33 percent ofthe heat loss is by air infiltration.

In the summer, air infiltration is a minor com-ponent of heat exchange in cooler northern cli-mates. Conversely, in hot arid climates summer airexchanges may be effective in decreasing the heatload on a home—hence the benefit of trees shadingthe roof and exposed walls.

Properly placed landscape vegetation reducesair infiltration by cutting the velocity near thehouse. Its effect on air infiltration will depend on theextent to which wind pressure rather than tem-perature differences is causing the air exchange.

Dead air space and double-pane windows reduceheat conduction.

Heat transfer also occurs via the buildingmaterials of the home. Heat conduction throughsolids is controlled by the thermal conductivity ofthe building materials, their thickness and the sur-face area available for heat flow (for example, areaof walls, floor, glass, or ceiling), and the tem-perature difference between the inner and outer sur-faces of the material.

Thermal conductivity is a way of comparing therate at which heat can be transferred through

materials—from a hotter to a cooler surface for astandard thickness, surface area, and temperaturedifference.

A layer of still air has the lowest rate of con-ductivity of materials commonly found in the home.Insulation is effective in reducing the rate of heatconduction because it traps air within its pores.

Most walls and ceilings are composites ofmaterials and reduce heat conduction by trappingair within or between the layers. Glass windows con-duct heat rapidly unless you use the double-pane orstorm window.

To reduce heat conduction, control the tem-perature difference between the inner and outer sur-faces of walls, ceilings, and floors.

The inner surface temperature is largely theresult of the interior air temperature. One way toconserve energy in winter is to lower the interiortemperature, thus reducing the temperature dif-ference between inside and outside surfaces.

Outside air temperature, wind velocity andsolar radiation, as well as the amount of heat beingconducted through the material, affect the outersurface temperature. Full sunlight can raise exteriorsurface temperatures to levels considerably abovethe outside air temperatures, but this difference willbe reduced somewhat at higher wind velocities.

Landscape vegetation can reduce the amountof sunlight reaching the outer surfaces of a house. Itthereby reduces the temperature difference betweeninner and outer building surfaces in summer whenheat is being conducted rapidly into the home. Inwinter, however, sunshine on the building’s outersurfaces can help reduce heat loss, and winter shadewould interfere. Only deciduous plant materialshould be used close to the house on the east, south,and west exposures.

Heat conduction generally represents from33 to 50 percent or more of the total heat exchangebetween a house and the surrounding environment.

A third and highly variable mechanism for heattransfer into homes is solar radiation transmittedthrough windows or other glazed surfaces. Radia-tion transmission is essentially a one-way process.Short-wave radiant energy from the sun can passeasily in through the windows, but long-wave radia-tion from inside the house cannot be transmittedback out.

Obviously, the size, position, and type of win-dows in a home relative to the position of the sun inthe summer and winter sky greatly influence therole of transmission in home heat exchange. Vege-tation around a home also can influence radiationtransmission by blocking sunlight to windows atmidday.

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A microclimate includes the buildings and treeson your property and those in the vicinity.

Other characteristics of microclimates includeground surface and vegetation. Dark ground sur-faces absorb more heat and reflect less than lightsurfaces; smooth surfaces reflect more heat thanrough surfaces; the amount and character of thevegetation affect the amount of heat absorbed orreflected. Vegetation, in general, absorbs more andreflects less than bare ground and water.

Site SelectionCarefully choose your building site. On a farm

there may be more choice sites. On a lot in town youmay be able to break away from the traditionalhouse placement depending on the grid system ofthe streets.

The optimum site would be a gentle slope witha south to southeast exposure. If a less favorable sitemust be selected, architectural style and landscapeplanning become even more important.

In the new additions of some Kansas com-munities, developers have made better use ofchanges in topography: in some places the roadsfollow the land. The result is a wider choice of lotson which to landscape and build with energy con-servation in mind.

The optimum structure orientation for a house inKansas is south 20 degrees east.

An ideal building lot has clumps of healthy,deciduous trees on the south, southwest, and westsides of the building site and a well-established windbreak made up mainly of evergreens on the northand northwest.

Structure OrientationOn any site, it is critical to orient the house for

optimum solar benefit. Place a rectangular homewith its long axis in an east-west direction. Formaximum winter solar heat gain, south 20 degreeseast is optimum. That allows the setting sun to heatthe northwest wall of the building. During the sum-mer months this orientation would aid the roofoverhang in shading the south-facing windows.

Good roof designs provide overhangs that createshade over south-exposed walls and windows.

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Architectural StyleNext to orientation, the building design is im-

portant if you want to take advantage of solarenergy.

Considerable energy can be conserved byplanting shade trees, but they take time to grow. Inthe meantime, a good roof design with overhangscan create immediate shade over south-exposedwalls and windows. An adequate roof overhang andcorrect window placement can keep out the summerrays and admit the maximum winter sunshine.

Like sails on a sailboat, side-hinged casementwindows catch the breeze.

Correct window types can capture summerbreezes as well as direct the flow of cooling air. Forexample, low-placed louver windows allow airflow atfloor level. Side-hinged casement windows catchbreezes like a sail (they can also sail off in a strongwind). Many modern windows have good insulationfeatures that should be included in any windowdesign.

In the past, architectural balance dictated theplacement and style of windows. Today, function isconsidered of equal, if not greater, importance.When deciding where to put the windows, study theprevailing wind flow pattern and the beneficial sum-mer breezes, as well as winter winds.

To conduct air currents, a house must haveboth inlets and outlets. Maximum air flow occurswhen large openings of equal size are placed op-posite each other. Highest wind speeds occur when

A plan view: Interior walls should be designed soair moves through the house easily.

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a small inlet is combined with a large outlet. Internalwall structure should be designed to facilitate airmovement through the house.

The garage can help regulate a home’s mi-croclimate. For instance, an attached garage onthe north side of a house can block winter winds ifthe opening is to the east. A garage on the west sideof the house can control solar heat gain in the sum-mer. A protruding or free-standing garage canprovide a protected area for a patio.

Low-placed louvered windows allow air flow atfloor level.

The entrance can help control energy costs.The main entrance should be protected from the hotsouth wind and cold winter wind.

Ideally, an entry should have a protectiveoverhang and an airlock hallway. A well-placedshade tree can serve as the overhang. Airlock hall-ways are found in many older homes. Sometimescalled a vestibule, this closed-off entrance keepscold air from rushing into the living quarters in thewintertime and the cool air from escaping in thesummer.

An airlock entry is protected from the wind andsummer sun.

Attached GreenhousesMany homeowners today choose to build an at-

tached greenhouse to help reduce heating costs.


Heat energy enters the greenhouse as shortwaves, is absorbed by objects, and is re-radiated aslong waves. These long waves do not readily escape.The captured heat is known as the “greenhouse ef-fect .”

The greenhouse can be considered a solarcollector for the home. The collector can be a solidnorth wall or any object in the greenhouse. Thesun’s rays are transmitted most effectively at anangle of incidence perpendicular to the light source.The angle of incidence refers to that angle at whichthe sun strikes a collector surface. The physicalproperties of glass (as well as the number of layers)influence the amount of energy entering the green-house.

Solar energy is stored in the objects it strikes,and the amount stored depends upon the object’ssurface texture, color, density, the conductivity ofthe material, and the temperature of the surround-ing air.

Although light reflective surfaces are essentialfor plants to grow, dark surfaces absorb and con-serve more heat. The solution to these conflictingneeds is a compromise, such as a grey or tan wall.

The type and design of the thermal conductorsused to make connections between the greenhouseand the house will largely determine the energy ef-ficiency of the greenhouse. As a heat source, it isusually best to have more than one heat collector.Both the floor and north wall should be constructedof rock or concrete blocks filled with sand or othermaterials.

For the person designing a new home, a moreelaborate greenhouse design may be incorporated.Designs that circulate warm air through the floorstructure of the house or those that circulate warmair around the envelope of the house are energy-efficient. Such designs only require a small auxiliaryconventional system to help with temperature ex-tremes.

The greenhouse effect occurswhen heat energy enters thegreenhouse as short waves andis absorbed and reradiated inlong waves.

PatiosThe location of a patio or deck will determine

its usefulness. in the summer, for early morningbreakfast, a northeast location is ideal. For eveningentertainment, a south or eastern exposure is pref-erable. A western exposure is only useful when am-ple shade trees or taller shrubs control the glare ofthe setting sun. A southern-exposed patio has thedisadvantage of excessive midday heat.

Selecting and placing shade trees carefully canovercome this problem. A patio with a southern ex-posure next to the house reflects heat through thewindows into the home during winter. When asouth-exposed patio has no area near it to plantdeciduous shade trees, an overhead trellis coveredwith a fast-growing deciduous vine can provide thenecessary shade.

An attractive, well-designed patio encouragescooking out in the summer which conserves energyby not heating up the kitchen.

A vine on a trellis can shade a patio.

GlareGlare from natural and artificial surfaces can be

annoying and disturbing. Take into account theglare producers around your home and yard andplan to minimize them when you plant trees andshrubs.

Hot air is forced around the en-velope of the house, creating aprotective layer. It radiates intothe house and can be ventedduring the summer.

Hot air is forced through thefloor and radiates into the house.

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Glare is the result of reflecting light. Be awareof the glare from a body of water, sand, gravel, orsnow. On a bright day, even the sky can make yousquint. Notice too, if there is glare from concretebuildings nearby, or from the street surface, win-dows, or parking areas.

You can control sky glare by planning to screenthe light coming in from above. To decrease theglare from a patio, plan to block glare from beloweye level.

Window glare, which may only occur at certainhours of the day, can be minimized by placing asmall tree or attractive composition of trees in thepath of the annoying reflecting rays.

Driveways and Parking AreasShade trees can make a difference near the

driveway and parking areas. Cars parked in theshade do not heat up as much from the sun so thiscuts down on your need for the air conditioner in thecar.

A car sizzles in sun but stays cool in shade.

Play AreasWith good landscape planning to make ample

shade available, children can play outside duringthe summer in the early morning or afternoon.

Children need two areas to play in—openspace, such as a lawn to run on, and a more privatearea. Fast-growing trees provide adequate shade fora play area. For instance, five small cottonwoodsplanted close together provide adequate shade andgive the children a feeling of being “in the woods.”

When the trees start to crowd each other, all butone can be removed. It will stand as a reminder ofchildhood.

Play areas should be shaded to protect childrenfrom the summer sun’s intense heat.

Landscaping Guidelines

Energy-Conserving LandscapesLandscape design for energy conservation re-

quires a site-specific approach. Solutions come af-ter a careful site analysis. Good landscape principlesstill hold. Plant material, however, can no longer beused only for esthetics. Functional needs are para-mount and using plant material wisely can help en-ergy conservation.

Selecting PlantsWhen selecting trees, shrubs, and vines, you

should determine the hardiness of the particularplant, check soil conditions, space, and the sitecarefully. Plants should be selected for their ap-pearance as well as for their climate control quali-ties.

In selecting your plants, you should consultwith the nursery operators in your area. They arefamiliar with soil conditions and landscape featuresand should be able to advise you about the mostbeneficial plant material for your locale.

The plants should harmonize with or enhancethe architecture and the landscape.

Keep in mind that plants are divided into threecategories: deciduous (those that lose their leaves inwinter), evergreen, and broadleaf evergreens.

A shade tree which loses its leaves in the winterlets the sun’s rays reach the house.

Some deciduous trees and shrubs leaf out earlyin the spring, and others leaf out much later. Thisfactor should be considered when selecting shade

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A tree’s shade potential depends upon its canopy shape and the density of the shadow it creates.

trees for planting close to the house. Different shadetrees exhibit different shadow patterns; some covera larger area than others.

Some trees grow faster than others. Most fast-growing trees are not long lasting, therefore, thehomeowner might interplant the fast-growing withslow-growing species. It is best to plant large shadetrees. For a tree to become a functional shade treein a few years, it should be 12 to 18 feet tall whenplanted. A tree this size should be transplanted by aprofessional.

(On the other hand, when working with alimited budget, smaller trees can be planted. Withproper care a six- to 10-foot tree will grow fairlyrapidly, and some shade advantages can be realizedafter a few years.)

A shade tree planted near the corner of a househas room to grow and requires little pruning.

It is much cooler under a tree that completelyobstructs the sun’s rays than under one that onlyfilters the rays. As a general rule, plants with a light,smooth leaf reflect more of the sun’s rays than thosewith dark, coarse surfaces. For example, a shiny,smooth cottonwood leaf reflects more light than adarker, coarse bur oak leaf.

Before planting a shade tree, you should checkthe shade movement for the chosen location.

Adaptability and HardinessWhen you select trees and shrubs, adaptability

and hardiness should be major considerations. InKansas, plants have to be hardy to survive theweather extremes.

The homeowner should consider a plant’s adap-tability to its specific location on the property.

If you are selecting for the north side of thehouse, choose a fairly shade-tolerant plant. A north-ern location also requires extreme winter hardinessunless the tree is protected by evergreens.

For the south and west sides of the house, useplants adaptable to drought, sun, and hot winds.

The southwest corner of a brick house is atough place to grow plants. Hardy spireas and juni-pers will do well on the southwest; on the northeastcorner, more tender plants—such as mahonia oryew—could survive.

Root StructureWhen planting shade trees near the house and

patio, it is important to remember that trees havedifferent root growth habits. Some trees have shal-low lateral root systems, others have deep lateralroot systems, some have taproots, and some have acombination of root systems. All are influenced bysoil type.

Your selection should be governed by the depthof soil. To prevent foundation damage, a tree within10 feet of the house should have a taproot system.Such a tree would be well-anchored against the Kan-sas winds.

Examples of trees with a taproot system arepecan, Honey locust, black walnut, American sweet-gum, red mulberry, American hophorn beam, whiteoak, shingle oak, bur oak, and golden rain trees.

Branch StructureA well-structured tree will have branches

growing in all directions. Select trees with a strongbranch attachment for placement near the house.The locust tree, London Plane, and the male osageorange are inherently strong, and their branches donot easily snap off in storms.

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Some vase-shaped trees, such as the hackberry,are good shade trees to place close to the home.Their branches tend to sweep over the roof, as com-pared with the pin oak, the branches of which tendto sweep the ground.

Selective pruning can open up a tree that is toodense, allow wind to pass through, yet provideadequate shade. Correct pruning improves thestructural strength of the tree and lessens possiblestorm damage. A certified arborist can help youwith the needed corrective pruning, especially forlarger trees.

Vase-shaped trees planted close to the houseprovide adequate shade.

Wind ControlDuring winter, the wind may be intercepted,

diverted, or channeled through obstructions such asfences, walls, or plants. The key to controlling win-ter winds is to diffuse them, not to block them. Useevergreens and deciduous plants in combination todiffuse the wind.

Channel the summer wind by selectively plac-ing the shrubs and trees.

Plants can help channel breezes across a patio.

Directing the wind around and over plants ad-jacent to buildings will enhance natural ventilation.

A grouping of shrubs can lift cool breezes into awindow or channel the wind flow across a patio.Generally speaking, the air under trees is movingfaster.

Provide an evergreen windbreak to break thestrong wind from the north and northwest.

Using Plants to Conserve EnergyPlant large deciduous shade trees on the

southern, southwestern, and western sides of thehouse. Deciduous trees block the summer sun butlet the winter’s warming sun through. Plant the treesapproximately 15 to 25 feet apart and 10 to 15 feetfrom the house. Plant the strong-wooded oaks (red,scarlet, or bur), linden, London Plane, or ash, toavoid wind damage to the house. (Check for adapt-ability for your locale.)

Keep these orientations free of evergreen treesthat will block winter sun. A recent study showedthat a difference of eight degrees Fahrenheit be-tween shaded and unshaded walls was equivalent toa 30 percent increase in insulating value needed forthe shaded wall.

Plant deciduous vines so they climb directly onthe southern and eastern walls of a brick or masonry

A hinged trellis can be lowered for maintenance.

house. They block summer sun but allow the wintersun in. If the house is wooden, build a trellis next tothe walls and encourage vine growth on the trellis.

(Hinge the trellis at the base so you can lower itto paint the wall without seriously disrupting thevines.)

Plant deciduous or evergreen trees and shrubson the eastern, southern, and western sides of anoutdoor air conditioning condenser. The hotter acondenser gets, the harder it has to work. As much

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as a three percent savings in the efficiency of the airconditioning system can be realized simply byshading the condenser from the summer’s hot sun.Be sure to allow ample space for air to circulate.

Plant large deciduous shade trees on thesouthern, southwestern, and western sides of out-door summer activity areas. In addition to coolingthese areas, they provide a “roof” for this outdoorliving room.

To block the winter wind on the north andnorthwest sides of the house, plant two or morerows of evergreen trees together with deciduoustrees. Remember that a windbreak provides thegreatest reduction in wind velocity at a distance offive to seven times the height of the windbreak onits leeward side. Winter energy consumption hasbeen reduced as much as 30 percent by a wind-break.

Plant dense evergreen shrubs on the western,northwestern, and northern sides of the house toprovide additional insulation against cold air in-filtration. Broadleaf evergreen vines also will helpreduce air infiltration.

To channel the southwesterly summer breezesinto and through the house, plant trees and shrubsthat will act as wind tunnels.

This may involve selective pruning or thinningout lower branches of understory plants (the smalltrees and shrubs) to promote maximum air cir-culation.

When living on a hill, be sure that the groups ofshrubs and trees you select will allow natural down-hill flow of cooler air. This will promote more circu-lation in the summer and avoid creating “cold airlakes” near the house in the winter.

Where feasible, deflect the air from exhaustvents and air conditioners away from the heavy useareas of the house. These sources of hot air ideallyshould be exhausted into northern orientationswhere heat excesses are not so severe.

WindbreaksA windbreak is an obstruction perpendicular to

wind flow that alters the wind direction. The windmust move over and around the obstruction. Thisalteration creates a small area on the windward sideof the windbreak and a larger area on its leewardside that offers protection from the full force of thewind. Windbreaks that allow some wind penetrationimprove the windbreak’s effectiveness. The objec-tives of windbreak design are to achieve enoughheight to create protection for the desired distanceon the leeward side of the windbreak, and to achieveenough wind penetrability to reduce the effects ofeddy currents and the leeward vacuum around thewindbreak.

To design a successful windbreak, keep thesecriteria in mind.

1. A good windbreak, in cross section, has ver-tical rather than sloping sides.

2. A windbreak should extend to the ground.3. A windbreak should be four to five staggered

rows wide if deciduous plants are selected.4. Within the windbreak’s width, species height

should be varied to create rough edges.The protective zone created by a windbreak

with these characteristics extends leeward for adistance equal to 30 times the height of the wind-break. Maximum protection occurs at a windwarddistance of five to seven times the height.

Distance from Windbreak Percent of Wind(in units of windbreak height) Speed Reduction

2 ½ times the height 10-205-7 5010 30-4015 10-2020 1030 less than 1

Windbreaks work most efficiently when their lengthis 11.5 times greater than their mature height. -

Windbreaks alter and direct the wind flow pattern to protect the house from the wind’s full force.

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Ground cover eliminates mowing around treesand channels breezes.

Wind ChannelsWindbreaks are designed to block wind; wind

channels are designed to guide its circulation. Thisis accomplished by deflecting wind currents intospecified locations. Materials must be fairly im-penetrable, but they must be oriented so that thedeflected wind is funnelled into a desired areawithout decreasing the initial velocity.

Evergreen plants with dense foliage extendingto the ground, such as red cedars, could be plantedso that the branches of one mature plant will overlapwith those of its neighbor. By aligning the row oftrees toward the northeast, a southerly summerbreeze can be captured and directed into the area onthe north side of a house. In this case, a southerlybreeze is converted into a southwesterly breeze.

Deciduous shade trees with dense canopies,like the male osage orange and bur oak, also can beused to create wind channels. As the wind strikesthe canopy, part of the wind stream will be forcedthrough the gap between the lower edge of thecanopy and the ground. In the process its velocity isincreased. A planting on the south side of a housewould promote internal air circulation within thehouse if the channel were directed into an open win-dow. It would also help shade the house from noon-time and hot summer afternoon sun. Low, denseshrubs placed underneath windows to the south ofthe shade tree would help circulate southerlybreezes through a house. The shrubs would deflect

Naturalistic planting in layers minimizes main-tenance.

wind upward and increase its velocity while theshade tree would deflect the wind into the house.

Not all plants with height and foliage densitycharacteristics conducive to wind control cantolerate continuous exposure to harsh winds. Thedesiccating effects of wind can kill many plants, par-ticularly in winter. Plants with brittle wood will notstand up well to winter wind exposure.

Designing a successful wind control devicerequires understanding the principles of wind con-trol and knowing how to use different materials totake advantage of these principles. It is equally im-portant to understand how the plants look againstthe surrounding landscape and how well they willhold up under exposure to the wind.

ConclusionThis publication is not all-inclusive. It is in-

tended to emphasize the functional use of plantmaterial in combination with other home designprinciples. A list of related reading material is in-cluded.

You should talk to an architect, a landscapearchitect who can help you design an energy-effici-ent home and landscape, and nursery operators who“design-build” and who can help you solve yourhome landscape problems. Remember, a combina-tion of many factors gives you an energy-efficientand comfortable living environment.

Place trees and shrubs so that they help channelthe breezes through your windows.

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The following is a partial listing of related publica-tions available from the Kansas Cooperative Exten-sion Service and your County Extension Office.

Pub. #C-562C-581C-568C-468

MF-434MF-317

C-550MF-353MF-452

MF-454

MF-438MF-440XC-391XL-133XL-134MF-650

TitleResidential Landscape DesignNaturalistic LandscapingFarmstead LandscapingGroundcovers, Rock GardenPlants and Ornamental GrassesAnswers to What Shall I PlantPlanting Ornamental Trees

and ShrubsAll About PruningSelecting a Grass for Your LawnPlanting Your Cool Season

LawnImproving Your Lawn

by OverseedingMowing Your LawnWatering Your LawnFertilizing Lawns in KansasPerennial Flowers for KansasAnnual Flowers for KansasHedges for the Home Landscape

Additional ReadingsEckbo, Garrett. 1956. The Art of Home Landscaping. New

York: McGraw-Hill, Inc.Environmental Design Press. 1977. Landscape Planning

for Energy Conservation. Reston, Va.Fisher, Rich and Bill Uanda. 1976. Solar Greenhouses.

Santa Fe, N. M.: John Muir Publications.Hightshoe, Gary. 1978. Natiue Trees for Urban and Rural

America. Ames, Iowa: Iowa State University ResearchFoundation.

Mazria, Edward. 1979. The PassiveEmmaus, Pa.: Rodale Press.

Olgyay, Victor. 1963. Design withN. J.: Princeton University Press.

Robinette, Gary. Roofscape. Reston,Design Press.

Solar Energy Book.

Climate. Princeton,

Va.: Environmental

. 1972. Plants, People, and Environmen-tal Quality. Washington, D. C.: United States Govern-ment Printing Office.

University of Minnesota. 1979. Earth Sheltered HousingDesign. New York: Van Nostrand.

Weber, Nelva. 1976. How to Plan Your Own Home Land-scape. Indianapolis, Ind.: The Bobbs-Merrill Com-pany, Inc.

Please check your local library and your nursery foradditional tips on energy-efficient planting.

All KEES materials and programs are available withoutdiscrimination on the basis of race, religion, nationalorigin, sex, handicap, or age. Anyone who feels that heor she has been discriminated against should send acomplaint within 180 days to the Department of Energy,Office of Equal Opportunity, Washington, D. C. 20585.This material is made available through federal Depart-ment of Energy grant funds under P. O. 94-385 and isdistributed by the Technical Energy Information Serviceof the KSU Cooperative Extension Service under con-tract to the Kansas Energy Office.


Brand names appearing in this publication are for product identification purposes only. No endorsement is intended,nor is criticism implied of similar products not mentioned.

Publications from Kansas State University are available on the World Wide Web at: http://www.oznet.ksu.edu

Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, creditGustaaf A. van der Hoeven, Energy Efficient Landscaping, Kansas State University, November 1982.

Kansas State University Agricultural Experiment Station and Cooperative Extension Service

C-627 November 1982

It is the policy of Kansas State University Agricultural Experiment Station and Cooperative Extension Service that all persons shall have equal opportunityand access to its educational programs, services, activities, and materials without regard to race, color, religion, national origin, sex, age or disability. KansasState University is an equal opportunity organization. Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June 30, 1914, as amended.Kansas State University, County Extension Councils, Extension Districts, and United States Department of Agriculture Cooperating, Marc A. Johnson,Director.

File Code: Horticulture and Landscaping–6


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